May 2005 VoIP and IP TELEPHONY · VoIP and IP Telephony: Planning for Convergence in State...

Representing Chief Information Officers of the States

VoIP and IP TELEPHONY:Planning for Convergence in State Government

May 2005

VoIP and IP Telephony:Planning for Convergence

in State Government

May 2005

Representing Chief InformationOfficers of the States

NASCIO represents the state chief information officers from the 50states, six U.S. territories and the District of Columbia. Membersinclude cabinet and senior level state officials responsible for infor-mation resource management. Other IT officials participate asassociate members and private sector representatives may

become corporate members.

AMR Management Services provides NASCIO’s executive staff.

© Copyright National Association of State Chief Information Officers (NASCIO), May 2005. Allrights reserved. This work cannot be published or otherwise distributed without the expresswritten permission of NASCIO.

DisclaimerNASCIO makes no endorsement, express or implied, of any products, services or websites contained herein, nor is NASCIO responsible for the content or activities of any linkedweb sites. Any questions should be directed to the administrators of the specific sites towhich this publication provides links. All information should be independently verified.

VoIP and IP Telephony: Planning for Convergence in State Government

table of contents

Acknowledgements.................................................................................................................................................iv

Executive Summary.................................................................................................................................................1Changing Telecom Business Models....................................................................................................................1Using VoIP for Government Transformation..........................................................................................................1Considerations for Transformation........................................................................................................................2

Legacy Telephony Technology...............................................................................................................................3Public Switched Telephone Network (PSTN)........................................................................................................3Centrex.................................................................................................................................................................4

IP Technology Solutions Overview.........................................................................................................................6VoIP......................................................................................................................................................................6IP Telephony vs. VoIP............................................................................................................................................6IP Communications (Beyond IP Telephony)..........................................................................................................7Benefits of IP Communications over a Converged Intelligent Network.................................................................7

Economy........................................................................................................................................................7Flexibility........................................................................................................................................................7Resilience......................................................................................................................................................8Productivity....................................................................................................................................................8

Building Blocks of Converged IP Communications Networks...............................................................................8Network Infrastructure...................................................................................................................................8Applications...................................................................................................................................................8End Points (Client Devices)...........................................................................................................................9Call Processing..............................................................................................................................................9

Major IP Communications Solutions.....................................................................................................................9IP Telephony..................................................................................................................................................9

Considerations for Deploying IP Telephony........................................................................................................10IP Conferencing..................................................................................................................................................11IP Contact Centers..............................................................................................................................................12Unified Messaging..............................................................................................................................................12Rich Media Communications—Integrated Audio, Video, and Web Conferencing...............................................13IP Videoconferencing..........................................................................................................................................14IP Video Telephony.............................................................................................................................................14Extension Mobility...............................................................................................................................................14IP Telephony Applications...................................................................................................................................15Mobility Applications...........................................................................................................................................15

Softphones/Soft-agents...............................................................................................................................15802.11a/b/g Wireless LANs and Wireless or Soft IP Phones........................................................................16Teleworker / Support...................................................................................................................................16

Extended IP Communications Applications........................................................................................................17Emergency Alerting Applications.................................................................................................................17

Business Continuity / Disaster Recovery............................................................................................................17Land and Mobile Radio Convergence..........................................................................................................17N11 Services—211, 311, 511, 711 Services to Relieve Overburdened 911 Systems....................................17Video/Audio-On-Demand, E-Learning..........................................................................................................17

i


IP Telephony Implementation Considerations.....................................................................................................17A "Typical" VoIP Configuration............................................................................................................................19

The Economics of VoIP..........................................................................................................................................20Selecting the Right Products for Investment Protection and On-Going Management.........................................20The Business Case for IP Communications— Return on Investment (ROI) & Total Cost of Ownership (TCO) ..20Savings from Reduced Network Infrastructure Costs.........................................................................................22Savings from Improved Administrative and Operational Costs...........................................................................22

VoIP Implementation and Planning.......................................................................................................................24Centrex Replacement.........................................................................................................................................25

Common Centrex Migration Concerns.........................................................................................................26Considerations for Centrex...........................................................................................................................27

VoIP Support for Persons with Disabilities..........................................................................................................28

VoIP Implementation Technical Considerations.................................................................................................29Network Infrastructure—Advanced Intelligent Network Features.......................................................................29Cabling...............................................................................................................................................................29Network Infrastructure........................................................................................................................................29LAN Network Design..........................................................................................................................................30Power over Ethernet (PoE).................................................................................................................................30Quality of Service (QoS).....................................................................................................................................30Auto-Management Functions.............................................................................................................................32UPS and Power Backup.....................................................................................................................................33Multi-Layered, End-to-End Security Technologies..............................................................................................33Implementation Considerations—Centralized, Distributed, or Autonomous?.....................................................34Mix of Broadband, WAN, MAN, LAN, and PSTN.................................................................................................34Flexibility, Scalability, Resiliency, and Availability................................................................................................35Security...............................................................................................................................................................35Training, Support and Maintenance....................................................................................................................35E911 Considerations...........................................................................................................................................35Dial Plans............................................................................................................................................................36VoIP Vendors......................................................................................................................................................36

VoIP Regulatory Environment..............................................................................................................................38

The Vision of VoIP..................................................................................................................................................39

State CIO VoIP / IP Telephony Questions..............................................................................................................40Section I—General.............................................................................................................................................40Section II—Reliability/Quality of Service/Security...............................................................................................42Section III—Cost Benefits/Funding.....................................................................................................................44Section IV—Implementation/Management.........................................................................................................46Section V—Emergency Services/Disaster Planning...........................................................................................48Section VI—Technical........................................................................................................................................50Section VII—Applications...................................................................................................................................52

Links to Articles and Case Studies.......................................................................................................................53

VoIP/ IP Telephony Glossary of Terms..................................................................................................................54

ii


Figure 1. VoIP/IP Telephony as a Percentage of New Phone Lines Installed.............................................................1Figure 2. Public Switched Telephone Network (PSTN)...............................................................................................3Figure 3. Signaling Control Point (SCP) Functionality................................................................................................4Figure 4. Three Different IP Phone Configurations.....................................................................................................9Figure 5. Hybrid PSTN/VoIP Configuration..............................................................................................................18Figure 6. Reasons for Hybrid PBX Adoption.............................................................................................................18Figure 7. Simple VoIP Configuration........................................................................................................................19Figure 8. Average Payback of VoIP by Vertical Industry...........................................................................................21Figure 9. Sources of Savings from VoIP and IP Telephony Implementations............................................................23Figure 10. Connectivity Options...............................................................................................................................24Figure 11. IP Telephony Planning Estimates............................................................................................................25Figure 12. Jitter.........................................................................................................................................................29Figure 13. Conditioning Packets to Ensure Quality of Service..................................................................................31Figure 14. Segregating Packets by Delay Characteristics........................................................................................32Figure 15. Technology Support for the "Connected" Teleworker...............................................................................39Figure 16. OSI Layers—Signaling System 7 Protocol Stack....................................................................................42

index of figures and tables

iii

iv VoIP and IP Telephony: Planning for Convergence in State Government

NASCIO would like to express its utmost gratitude tothe Infrastructure Sub-committee's Chair, John P.Gillispie, COO, Information Technology EnterpriseOffice, State of Iowa, and to Tom Shepherd,Information Technology Enterprise Office, State ofIowa, for their tireless dedication that made this pub-lication possible. NASCIO would also like to thankthe following members of the Infrastructure Sub-committee for lending their time and expertise to thispublication:

� Dave Blackwell, Office of InformationTechnology, State of New Jersey

� Steve Dawson, CTO, State of New Jersey� Marty Dunning, SUN Microsystems� Gary Falis, Microsoft� Christian Fuellgraf, IBM� Michele Grisham, CISCO Systems, Inc.� Stan Herrera, CTO, State of Alaska� Lindsay Hiebert, CISCO Systems, Inc.� Larry Johnson, CIO, State of South Carolina� Denny Nincehelser, Telecommunications

Division Director, State of South Dakota

� Gail Ulan, CIO, Office of the Governor, Stateof Arizona

� Victoria Wallis, Engineering Manager, IowaCommunications Network

� Kathy Williams, Iowa CommunicationsNetwork

Finally, NASCIO would like to thank, DrewLeatherby, NASCIO Issues Coordinator, for his workon this project, and Doug Robinson, NASCIOExecutive Director, Jack Gallt, NASCIO AssistantDirector, Nancy Howard, AMR Marketing andCreative Services Director, and Chris Walls, AMRSenior Publications and Website Coordinator, fortheir guidance, editorial revisions and other assis-tance regarding this publication.

Please direct any questions or comments about VoIPand IP Telephony: Planning for Convergence in StateGovernment to Drew Leatherby at [email protected] or (859) 514-9178.

acknowledgements

1VoIP and IP Telephony: Planning for Convergence in State Government

Changing Telecom Business Models

The keen interest in Voice over Internet Protocol(VoIP) and Internet Protocol (IP) Telephony and its'accelerated adoption rate has led many to the real-ization that the long-established Public SwitchedTelephone Network (PSTN) voice business modelwill be facing its end of life in the next 10 to 15 years.Currently, VoIP business models are generally notwell understood, are highly dynamic, and are affect-ed by the organizations and vendors involved anddynamic regulatory issues. Standardization withinthe product lines and the promise of enhanced appli-cations and reduced operational costs have put VoIPand IP Telephony on the fast track in many organi-zations. (See Figure 1.)

This publication is intended to provide an under-standing of the fundamental issues facing organiza-tions as they assess VoIP and IP Telephony. It con-tains a description of the operation and functionalityof the legacy Public Switched Telephone Network(PSTN), an explanation of voice transport over theInternet and IP Telephony, and a discussion of theissues and drivers associated with the migration fromthe PSTN to converged voice and data networks.

executive summary

Figure 1. VoIP/IP Telephony as a Percentage ofNew Phone Lines Installed

Source: Gartner

Using VoIP for Government Transformation

Today's economic and social climate is causing gov-ernment to rethink how it operates. Efficient use ofshrinking budget resources, optimizing revenue col-lection, or deploying services to meet the demandsof a connected and "on demand" constituency, aresome of the requirements placed on governmentagencies. When increased security requirements areadded to this agenda, it is easy to see why govern-ment institutions must use transformationalapproaches and new technologies that enable trans-formation to change the way they operate to meetthese new and ever increasing requirements.

As a result, government chief information officers(CIOs) are being asked to do more with less:increase quality while cutting costs, launch new proj-ects with a smaller staff, standardize IT systems butreduce capital. At the same time, they have to ensurethat communication and information flows smoothlybetween agencies and protects all mission criticalapplications from potential security threats.

Given these new demands on government services,and rapid changes in society and technology, busi-ness as usual is no longer an option. Working hard-er or longer has ceased to deliver the expected ben-efits and the use of isolated technologies that deliverpoint solutions are increasingly costly to maintain,integrate, and manage. Instead, a different opera-tional approach and model is required. A transforma-tion model is needed that takes advantage of organi-zational best practices and embraces the efficienciesand increased productivity enabled by using the righttechnologies; an approach that provides flexibility forfuture applications to be smoothly integrated,extended, and supported with common practicesand infrastructure. VoIP and converged networktechnologies, along with proper planning processes,can make significant contributions to ensure trans-formation delivers effective results.

Transformation of government institutions means

(percent)

(year)

2 VoIP and IP Telephony: Planning for Convergence in State Government

better leveraging of resources—both human andtechnology. One example is setting up inter-agencycollaboration or optimizing citizen-services andshared government services. Transformationincludes not only changing the business of govern-ment, but also the governance process itself. Thisrepresents a major change in the way organizationsconduct their day-to-day operations, as well as howthey think about themselves (e.g. taking a customer-centric approach) and promises dramatic benefits forthose who reach their destination.

Transformation is a major undertaking. However,many organizations undertake the transformationjourney without a clear roadmap and the experienceof proven practices. As a result, these efforts neverreach their ultimate destination. So while VoIPTechnology and convergence technologies mayenable transformation to occur, they do not neces-sarily guarantee that transformation will take place,because transformation is linked to the way people,processes, and the organization itself serves its con-stituents. For these changes to take place, initiativesof a VoIP project must be linked to, and driven by, thetransformational initiatives as the key drivers. Thekey to the success of a longer term transformationalinitiative is that a proper framework is established ina cross-functional leadership team, that effectiveplanning and processes are put in place to guide thetechnology (all technology) rollouts, and that part-ners and partnerships must be established andmaintained for those who will help guide and supporttransformational processes.

Considerations for TransformationAlthough government decision makers may facetremendous budget pressures in trying to enact theirtransformation efforts, they need to keep their focuson the ultimate goal of transformation—e.g. produc-tivity increases, constituency satisfaction, and rev-enue generating opportunities—and not be contentto accept cost reduction as the only objective.

Today, business decisions and processes are drivingtechnology implementations. Equally important,technology serves to enable organizations to moreefficiently address business needs. Therefore, it iscritical that transformational VoIP projects link tech-nology decisions to government business objectivesand take into account the future goals of the organi-zation.

Before making fundamental changes to the existingprocesses, procedures, applications, and infrastruc-ture, CIOs should clearly understand and be able toarticulate the value that they expect from businesstransformation. What are the interim and terminalobjectives? What benefits are sought? What forceswork in favor and in opposition to the proposed trans-formation? How will changes in one area affectprocesses, applications, and personnel in otherareas? How can we minimize disruptions in servicesdelivery and employee productivity?

Most importantly, who (what partners and vendors)can bring the exact set of complimentary skills, prac-tices, and technologies that will lead organizations totheir desired destination and ensure that the goalsare achieved, not just marginal short-term benefits?


Public Switched Telephone Network (PSTN)

In order to understand the issues in replacing legacyPSTN systems with VoIP, it is important to under-stand the operational characteristics, and limitations,of each. (See Figure 2.)

The PSTN can be characterized by thinking of it asdumb devices driven by an intelligent network. In thePSTN, signals are sent between telephony switchesto set up and terminate calls and indicate the statusof terminals involved in the calls. These signals arecarried over a separate data network known as

Common Channel Signaling (CCS—represented bythe black lines in the diagram below). The protocolused by CCS is Signaling System 7 (SS7). Theentire system is called the Intelligent Network (IN).

Signaling Control Points (SCPs) are databases thatprovide information necessary for advanced call-pro-cessing capabilities. For example, an SCP would bequeried to determine the routing number associatedwith a dialed toll free 800/888 number or to validatethe personal identification number (PIN) of a callingcard user. (See Figure 3.)

legacy telephony technology

Figure 2. Public Switched Telephone Network

Source: Cisco Systems


Within the next few years, the existing PSTN willslowly be replaced by public packet networks. Duringthis transition, the PSTN will continue to be heavilyused because of the millions of users and non-IPdevices still connected to it. In addition, the PSTNsupports a variety of voice services through the sig-naling control points as illustrated above. An Internettelephony device needing to connect with one ofthese services must use PSTN signaling for the fore-seeable future.

CentrexCentrex is a service provider-based telephony solu-tion that provides business class telephony featuresto enterprises. Centrex is built on a carrier's centraloffice switch. The customer can have either analogphones, digital phones or both on their premises.The phones are then connected via individual copperpairs back to the central office switch. With largerCentrex implementations there may be accessnodes on the customer site's fiber connected to thecentral office to reduce the dependence on copperbundles to the central office.

The main components that comprise the Centrexservice are:

� Centrex lines (consisting of copper pairsaccess nodes or directly to the central officeswitch and its line card ports).

� Analog or digital handset.� Centrex features (e.g. Caller Line ID or Call

Center features).� PSTN connectivity.� Voice mail (optional).

The Centrex line charge is a monthly cost that canrange from as low as $20 per month for largeCentrex customers with multiyear contracts up to$40-$50 per month for small Centrex customers.This cost varies from carrier to carrier and is oftenreduced by one to five-year contracts. Contracts areusually written with minimum line commitmentthresholds. Often Centrex involves contract cancella-tion penalties which can diminish the return oninvestment for planned migrations that are outside ofthe end of lease contract dates.

Figure 3. Signaling Control Point (SCP) Functionality



The analog or digital hand set is the responsibility ofthe customer in most cases. While in the past thephone companies rented sets, most have moved outof that business. This means that enterprise cus-tomers must purchase or lease their phones. Costsfor hand sets vary, but even in large volumes theycan be as much as $250.

Centrex features provide enhancements like Callerline ID, Call Center Features, and SimplifiedMessage Desk Interface (SMDI) that are chargeable.(Note: SMDI defines a way a phone system providesvoice-mail systems with the information needed tointelligently process incoming calls.) Customershave the choice of using a hosted voicemail servicefrom the carrier or using their own voice-mail system.

When purchased from the carrier, voicemail is ashared system based on services located at the cen-tral office. Customers subscribe to the service on amonthly basis per account. If a customer chooses tosource their own voicemail system, it is typicallylocated at the customer premises. Connectivity isachieved through special analog Centrex lines andan SMDI link. These analog lines are typically moreexpensive than regular Centrex lines and the SMDIlink is a significant cost.

The cost of Centrex moves/adds/changes (MACs) isalso significant. With many customers averaging 1-2changes a year, MACs add considerably to the threeyear total cost of ownership.


VoIP

The term Voice over Internet Protocol, or VoIP, hasbeen used as a catch-all phrase in the industry torefer collectively to a large group of technologiesdesigned to provide Internet-based communicationsservices. More accurately, VoIP refers only to theunderlying transport protocol that encapsulates voicetraffic or voice media streams and allows them to becarried over data networks, using IP network tech-nologies or internet protocols. VoIP, however, is notIP Telephony, nor is it the more widely used industryterminology called IP Communications that refers toan even broader definition of communications net-working applications and technologies.

VoIP can be understood as simply a transport proto-col for carrying voice over any packet network, usu-ally between sites. The term convergence, alsosometimes referred as a multi-service network,refers to the integration of data, voice, and videosolutions onto a converged network infrastructure.

IP Telephony vs. VoIPIP Telephony refers to call processing and signalingtechnologies that are based on the open Internetprotocol family of standards that provide end-to-endvoice, data, and video communications services.These standards have been defined by the InternetEngineering Task Force (IETF) and the InternationalTelecommunications Union (ITU) to provide interop-erable networking and communications services forpublic carrier networks and for the Internet.

The key point is that IP Telephony is more than sim-ply VoIP (transport of voice over an IP network)because it also involves a larger family of communi-cations standards needed to deliver voice and videoservices in the enterprise using open packet teleph-ony. IP Telephony generally refers to the use of theH.323 signaling protocol used to setup, control andmanage voice and video sessions. Because theseservices can be easily deployed within a converged

network, using standard layer 2 and layer 3 networktechnologies, they provide significant benefits overtraditional voice circuit switch network technologies.A summary of these benefits from a technology view-point include the following:

� IP Telephony allows the communication callprocessing services to be located anywhere onthe network and to use packet networks, ratherthan the traditional Time Division Multiplex(TDM) networks for communications services.

� IP Telephony, unlike Hybrid IP-PBX technolo-gies, allows for services to be delivered over acompletely converged network, so that dualwiring and cabling and network equipment for,and connections to, PBX or Hybrid IP-PBXequipment is not required.

� IP Telephony allows support of communica-tions services for voice media in addition to avariety of media types and modalities—web, e-mail, instant messaging, video, and conferenc-ing services.

� A "true" or "pure" IP Telephony system pro-vides the capability to carry traffic across dif-ferent geographies, across and between manyvendors, spanning many countries, becausethey can interoperate with a variety of Internettechnologies and existing telephony technolo-gies more flexibly, with greater benefit andreduced costs.

These benefits and capabilities are in contrast to lim-itations with existing voice legacy technologies thatare built with TDM technologies. With legacy voicePBX and Hybrid IP-PBX systems, there is muchgreater expense and difficulty to: 1) accommodatedifferences in disparate technologies and equipment;2) traverse geographic boundaries; 3) manage manysites centrally; 4) change the way resources areused on the network; 5) traverse regulatory bound-aries; 6) deliver new communications services usingdifferent media types; and 7) provide the level ofintegration, ease of use, ease of access, and ease ofmanagement found in an IP Telephony system.

IP technology solutions overview


IP Communications (Beyond IP Telephony)

The foundation of a converged network are the capa-bilities and tools that allow an enterprise to flexibly,securely, and cost effectively carry any combinationof data, voice, and video packets across the samelinks, using the same switching, routing, and gate-way platforms. The properties of scalability, resilien-cy, fault tolerance, security, flexibility, and managea-bility are inherent in the converged network. To gainthe advantages of the converged network, applica-tions use the underlying services of network intelli-gence to ensure quality of service, availability, relia-bility, and security.

Applications also extend and amplify the capabilitiesof a converged intelligent network when they arebuilt to use the underlying IP networking protocolsand are based upon a server or network appliancemodel.

Beyond IP Telephony that primarily provides "dialtone" and "multi-media video conferencing services"using IP protocols, the term IP Communicationsrefers to the additional robust suite of communica-tions applications and technologies that take advan-tage of a converged IP communications networkinfrastructure.

IP Communications applications include applicationssuch as Rich Media Conferencing, UnifiedMessaging and IP Contact Centers. These applica-tions, like IP Telephony, eliminate the barriers of timezones and geographic distances between physicalsites and organizations. By using IPCommunications applications, governments can bet-ter connect constituents with services, while enhanc-ing the capability and value of those interactions byallowing for greater customization, support, and per-sonalization of services. Clients can obtain faster,easier access to services. Services can be sharedacross organizations and departments. Improvedcommunications, collaboration, and operationalprocesses can be enabled throughout governmentalentities. In short, IP Communications improves theability of the organization to leverage its resources toserve constituents flexibly and cost effectively.

IP Communications, then, is the broader term thatrefers to the entire suite of communication applica-tions and the intelligent converged network capabili-ties that are built to work together with IP networkingprotocols.

Benefits of IP Communications over aConverged Intelligent Network

The benefits of IP Communications applications overa converged intelligent network are derived from aseries of fundamental capabilities within IP networksthat provide for the advantages of economy, flexibili-ty, resilience, and productivity.

EconomyAs opposed to connecting elements and applicationsof a communications system using expensive legacyvoice technologies such as DS1 and DS0 line cards,trunk cards and digital signaling technologies, IPCommunications networks allow customers to buildnetwork communication services based on IP net-working technologies using Ethernet economics,often called silicon economics, or the application ofMoore's law for the historical delivery of rapidadvances in information technology or computingperformance.

Looking at the economies of IP Communications ver-sus traditional voice and PBX technologies, the costto connect a typical enterprise PBX system with con-nections to the PSTN can be found in the cost ofports, cards, and circuits. One Ethernet port canreplace 50 or more legacy voice circuits, line cards,and chassis equipment needed to provide equivalentservice. The key point here is that the costs are sig-nificantly less to provide connections to other sitesand to other applications. IP Communications ismore flexible because it allows the use of broadbandand voice technologies to support communicationsand systems needs.

FlexibilityAs opposed to connecting elements and applicationsof a communications system using legacy technolo-gies that are proprietary, monolithic, and restrictive innature, IP networking allows connections to be made


with virtual reach—resources to be distributed any-where as needed; economies to be gained by cen-tralization of gateway resources, circuit, and serverresources; and the use of many types of media andapplications to be brought together to facilitate com-munications within an organization. IPCommunications systems are also more capable insupporting mobility requirements, telecommuting,moves/adds/changes, centralized management, out-sourcing operations, extension mobility, desktopintegration, front office, back office integration andapplications, enterprise directories, and takingadvantage of emerging web innovations and servic-es such as instant messaging, presence, and mobil-ity. Beyond achieving a higher degree of securitywith the application of data networking technologiesfor secure voice, video, and data, IPCommunications are vastly superior over legacyvoice technologies in deploying and integrating wire-less LAN applications, IP video surveillance, IP videoon demand, streaming video, video conferencing,and rich media conferencing applications.

ResilienceWith business continuity and disaster recovery highon the agendas of many organizations, the resilien-cy of connectivity and abilities provided by IPCommunications to keep the organization connectedmake it an ideal candidate for survivable services.Redundancy is built into intelligent layer 2 and layer3 networking technologies and applications.Clustering and hot standby technologies, fault toler-ant storage technologies such as RAID, dual powersupplies, and UPS systems are now common in theindustry. Internet protocols offer superior failover,redundant and self-healing capabilities that are easyto deploy, open standards based, and can supportnot only voice, but all of an organization's communi-cations services. The fact that the most resilient mil-itary and enterprise communications systems cannow use IP Communications and Internet protocolsto achieve five nines of reliability and availability pro-vides a superior alternative to rigid voice technolo-gies. These legacy technologies are far more expen-sive, and are unable to provide the overall systemresiliency needed for as broad a range of servicesand applications as can IP Communications.

ProductivityWith the shift of focus moving from savings toenabling end users to become more productive withapplications that help them accomplish higher quali-ty communications more quickly and easily, it is easyto see why IP Communications is superior to legacyvoice technologies. Custom IP phone applicationscan be provided that use any existing web or enter-prise database on an IP network. End users can takeadvantage of open enterprise directories; e-mail sys-tems for sending, receiving voice mail, fax, and e-mail messages; and use general tools for program-ming communication rules. Voice recognition tech-nologies and softphone support at the desktop canbe added to an IP Communications environment.While all of these possibilities also exist for legacytechnologies, they are more expensive, less scala-ble, and more difficult to deploy.

Building Blocks of Converged IPCommunications Networks

Typically, the following components are required tobuild a converged IP Communications network:

Network InfrastructureThis includes the intelligent switches, routers, andspecialized components (such as gateways, servic-es, and software) that form the physical infrastruc-ture and deliver intelligent network services such assecurity, quality of service, and resiliency to the IPCommunication infrastructure and applications.

ApplicationsThe real power behind convergence is found in thenew capabilities provided by integrated data-voice-video applications such as Rich MediaConferencing, Unified Messaging, and IP ContactCenter applications. These applications work bettertogether in a secure IP Communications networkdue to the trunk-less and port-less nature of IPCommunications, as well as having the ability to usethe innovations of web-enabled technologies andapplications that continue to drive communicationsinnovations and productivity.


End Points (Client Devices)The access points for users to take advantage ofapplications. These can be IP phones, personal dig-ital assistants (PDAs), mobile phones, and applica-tions for personal computers such as softphones.

Call ProcessingThe heart of any IP telephony system is call pro-cessing software that can run on network applianceservers or third-party servers.

Major IP Communications Solutions

IP Telephony IP Telephony provides the benefits of advanced dialtone and enterprise class telephony features andcapabilities, improved support for mobility and call pro-cessing services over a converged packet network.

IP Telephony thereby eliminates the need, cost, andexpense of running separate voice and data net-works. Because IP Telephony is more flexible, open,and adaptive than legacy voice environments, it alsoreduces expense, provides for better and more pro-ductive applications, and improves an organization's

ability to extend capabilities on its' network. IPTelephony also supports voice in addition to dataapplications that can be delivered to the IP phone orsoftphone from web services, backend / front enddatabases, or office systems. IP phone serviceapplications include enterprise directories, emer-gency alerting, Amber Alerts, support for N11 servic-es, kiosk applications, and custom applications.

IP Telephony allows organizations to reuse theirexisting network infrastructure. With IP Telephony,employees can use IP hand sets or softphones any-where on the corporate network. Generally only asingle Ethernet port is required to provide both desk-top and IP Telephony (voice) services. Power overEthernet using the 802.3af standard or pre-stan-dards based power can be used with great advan-tage throughout an IP Telephony environment topower other network appliances such as 802.11a/b/gwireless access points, IP video surveillance camerasand IP phones. IP Telephony systems also provide theadvantage of lower cost moves/adds/changes admin-istration allowing employees and departments tomore easily move from location to location withoutthe burdens of administration and service interrup-tion. (See Figure 4.)

Figure 4. Three Different IP Phone Configurations

Source: Avaya


Because IP Telephony works with packet networks,the model of support used for IP Telephony can bethe same as the one used for the desktop, therebyreducing and simplifying staffing requirements. Sincethe IP phone or softphone is an intelligent endpointon the network, it has the intelligence to seek outcommunications services from one or many IPTelephony call processing services. In addition, clus-tering and high availability networking technologiesprovide for a much more business resilient environ-ment at a far lower overall cost.

As mentioned above, IP Telephony can be used to:1) supplement; 2) extend; or 3) replace existingvoice services that are provided by legacy voicetechnologies.

Applications of IP Telephony include connecting it toan existing PBX environment and using IP Telephonyand its applications to support mobile workers andtelecommuting applications with a combination ofsoftphone and VPN services. Because workers canbe more flexible and IP Telephony can supportextension mobility (hotdesk) applications, enterpris-es and organizations can save real estate costswhile increasing the productivity of their workforce.Typically, productivity can be increased from 10 per-cent to 20 percent while increased flexibility andreduced costs from IP Telephony can account for anadditional 15 percent to 20 percent of cost savings. Insome cases, the cost savings are very high. This istrue in Greenfield sites (new sites), where the singleIP telephony cabling infrastructure, single networkinfrastructure, and one set of common operations arerequired to support data, voice, and video services.Most organizations plan their migration to IPTelephony based on key events or needs to evolvetheir infrastructure to IP Communication over time.

Typical requirements for an IP Telephony solutionare the converged network components consisting ofswitches and routers that provide for quality of serv-ice (QoS), security, in-line power, and virtual localarea networks to provide control and separation ofvoice, video and data traffic, as well as wireless traf-fic. In addition, management tools and protocols thatsupport the ability to ensure multi-service networkingtraffic such as real time and streaming video can alsobe supported and accommodated with appropriate

QoS tools. The ability to support a robust set ofgateway technologies to enable connections to anybroadband technology, or PSTN technology, (voiceinterface cards and WAN interface cards) and sup-port for protocols that handle multicast, and/or net-work content distribution, caching and filtering (forvideo on demand, etc.), as well as secure wirelesstechnologies, are other considerations for evaluationof the converged network infrastructure.

Considerations for Deploying IP Telephony

When deploying IP Telephony, there are several pre-requisites that should be considered within a networkreadiness assessment.

� Does the organization have category 5 wiringthat supports full duplex? (note: category 3wiring is also possible, although not recom-mended)

� Can the access switches support in-linepower?

� Are the switches capable of supporting priorityqueuing?

� Is the organization currently using 10/100switched networking technologies within theinfrastructure, or still using something less thanthis?

� How many sites will ultimately be tied togetherand supported with one IP Telephony server(or server cluster)? One? Three? Five? OneHundred?

� How are these sites networked together now?� What is the bandwidth between these sites?� Is the bandwidth QoS enabled in terms of

latency, delay and jitter?� Is there sufficient bandwidth to support the

voice between the sites?� What type of PBX technology will the IP

Telephony system be connected to?� Is voice mail or unified messaging services

also needed?

Extended applications of IP Telephony also includesupport for Enhanced 911 services so that IP phonesand IP devices are automatically located on the net-work, regardless of their physical location. IP


Telephony also provides support for extension mobility,also called hoteling or hot-desking, providing theability of any employee to have their extensionappear on designated IP phones. Softphones pro-vide the ability to use virtual private network (VPN)technologies and PC desktops or laptops to gainaccess to corporate communications services fromanywhere in the world without incurring toll charges.

In summary, IP Telephony generally provides an organ-ization with a higher level of productivity and flexibility,and reduced capital and operating cost. In addition,IP Telephony, as an application, is deployed to:

� Better handle growth, change, and complexity.� Support more economical communications

with Toll By Pass, VPNs and broadband tech-nologies.

� Providing ongoing operating savings with net-work simplification—infrastructure conver-gence.

� Provide for ongoing savings, efficiencies withstaff convergence and coordination.

� Improve the overall quality of all communica-tions services in terms of availability, securityand flexibility.

� Support the convergence of managementfunctions (centralized management) on thenetwork.

� Improved workforce mobility and productivity.� Increase business resilience, continuity and

provide for improved disaster recovery.

IP Conferencing

IP Conferencing, or IP Audio Conferencing, providesorganizations with the benefits of using secure on-net IP Conferencing resources to save significantexpenses over using alternative legacy voice confer-encing equipment connected with TDM equipmentand circuits or conference services that are support-ed by a service provider. The advantage of IPConferencing is found in the fact that the conferenc-ing resource can be located anywhere on the net-work and can use existing IP converged networkbandwidth, as opposed to expensive stand-alonevoice circuits to support the conferencing service,including the ports and cards to connect, support and

terminate conference calls. This is generally true,whether the legacy voice conferencing service or IPconferencing service is outsourced or not.

IP Conferencing can be supported either with soft-ware or hardware resources and is typically providedin terms of the number of simultaneous ports (users)of conferencing that the system can support. With IPConferencing, resources can be more easilydeployed, pooled, aggregated from anywhere on aconverged network, and more easily accessed andused by any user from any location. IP Conferencinggenerally rides on IP WAN networks that alreadyexist within the enterprise, meaning that essentiallyIP Conferencing rides for free, or for relatively littleincremental cost, over what is already provided.

Typically, IP Telephony systems and IP endpointshave a certain basic amount of IP Conferencing sup-port built in. This is one of the additional advantagesof an engineered IP Communications system vs. aHybrid IP-PBX. In general, the basic IP Telephonyfeatures that support IP Conferencing provide any-where from three to six sessions of IP Conferencingin ad-hoc IP conferencing scenarios. This meansthat any IP phone user can add up to five additionalparties, using IP conferencing by simply hitting the IPconferencing button over an IP network. This capa-bility is provided within the IP Telephony systemusing IP phones or softphones.

With IP Conferencing, speakerphone capabilitiesbuilt into endpoints also enhance the overall produc-tivity of workers using conferencing services. Forreservation-less and scheduled audio conferences,an IP Conferencing bridge or resource is needed.This resource can be provided with software or hard-ware resources.

As a general rule of thumb, most organizationswould require anywhere from 5 percent to 10 percentof their employees to be IP conference ports. In larg-er organizations, nearly 50 percent of all voice trafficminutes are terminated on conferences, so this num-ber may be higher.

The most significant benefit of IP Conferencing isincreased workforce productivity. When employeesare provided with conferencing resources that are


available, accessible, and easy to use, productivitygoes up. From an organizational perspective, IPConferencing provides the benefit of predictable andnear zero cost of operations, after the initial invest-ment for hardware or software IP Conferencingresources, since the service is supported on the con-verged IP network. IP Conferencing services arealso more easily grown, changed, and supported.

IP Contact Centers

IP Contact Centers provide organizations with thebenefits of using server based resources that inte-grate the functions of Interactive Voice Response,Automatic Call Distribution, and Call Flow Scriptinginto general purpose service based appliances thatcan be added to an IP Network to support sophisti-cated customer service applications. Within the pub-lic sector environment, IP Contact Centers allowlocal, state and federal government agencies todeploy integrated shared services, 211/311 services,and web portals to serve their constituencies.

Because IP Contact Center services use web basedtechnologies and use IP to connect components ofthe customer contact center together, they are notsubject to the distance limitations or the prohibitivelyhigh costs of maintenance and support as found intraditional voice legacy contact center technologies.This allows IP-based Interactive VoiceResponse/Automated Call Dispatching (IVR/ACD)and Customer Contact Center agents to be locatedanywhere on the network and to use IP Networkingtechnologies in addition to PSTN technologies tosupport contact center operations.

IP Contact Centers allow for media blending, globalqueues, and global reporting. Media blending is theability to support voice, web, and e-mail with a com-mon process and customer contact in-box. Thisallows one set of agents the ability to respond morequickly to all forms of communications with one vir-tual blended case queue.

IP Contact Centers provide the ability to support skill-based routing, time of day/day of week routing, andcentralized reporting over an IP network. This allowssites and various contact center operations to be

consolidated or distributed more easily and contactcenter operations as well as agents to work fromanywhere in the IP converged network. Call Flowscripts can be updated, and with web based admin-istration, operations can be centralized. New servic-es can be deployed consistently, quickly and easilyto sites anywhere in the world. IP contact centersalso provide the ability to support continuity of oper-ations more easily and cost effectively with resiliencybuilt in, and the ability to outsource contact centeroperations to other countries or geographies. Lastly,IP Contact Centers provide the ability to achievemuch higher levels of staffing efficiency, and work-force productivity with superior integrated desktoptools, better access to databases, and the ability toconsolidate operations over a converged IPCommunications network.

Unified Messaging

Unified Messaging (Unified Communications) is anIP Communications application that streamlinesworkers' message management burden and pro-vides for increased productivity and responsiveness.Having to check messages in a variety of formats allday long—e-mail and voice-mail on multiplephones—can be a full-time job in itself.

Collapsing all of these messages into a single mail-box and allowing employees to retrieve those mes-sages in the format handy to them at a given time("listening" to e-mail, "reading" voice-mail, for exam-ple) is a huge time-saver. The Radicati Group, aresearch firm in Palo Alto, California, estimates thatunified messaging generates 25 to 40 minutes ofadditional productivity per employee per day.

Like IP Contact Centers and IP Conferencing, andother applications of IP Communications, UnifiedMessaging also allows organizations to use the port-less and trunk-less model when provisioning com-munications services in an IP Communications envi-ronment. That is, rather than being required to useexpensive line cards and digital voice circuits, whenriding over a converged network, supporting voice,fax, and e-mail messaging requirements are muchmore economical. Ethernet is one to two orders ofmagnitude less expensive than purchasing bandwidth


using DS0 or DS1 technologies, and IP Networkingis much more flexible.

Unified Messaging also allows an organization totake advantage and reuse assets that they alreadyhave in place to support voice messaging require-ments. For example, if an organization is usingMicrosoft Exchange or Lotus Notes e-mail servers,they can also use these message stores to supportstorage for their voice and unified messaging needs.This allows an organization to centralize their voicemessaging resources to save additional capital andoperational expenses from equipment, operations,and software licenses. At the same time, UnifiedMessaging also "voice enables" the e-mail infra-structure, so that employees can now receive, listento, and respond to important e-mail messages, fromtheir cell phones, any IP phone, any web portal, orany public phone.

Not only are common server and software messagestores much less expensive for storage of voicemessages than their proprietary voice counter-parts,they also can be managed, centralized, distributedand support a wider variety of media and differenttypes of messages with a common in-box.Additionally, Unified Messaging can be furtherextended with voice recognition technologies thatallow access to corporate directories, conferencingservices, or personal address books that are voicedirected and voice activated, in addition to singlenumber reach capabilities and alerts that can be pro-vided to any cell phone or pager for message man-agement. Unified Messaging comes with built-in timeof day/day of week automated attendance andscripting rules that can further automate messages,group distribution lists, and broadcasts to depart-ments, workgroups and outside callers.

Like IP Communications and softphones, UnifiedMessaging can be accessed from anywhere over anIP Network using VPN services. It provides muchstronger support for mobility workers and telecom-muters while saving on long distance costs. Unifiedcommunications generally integrates with, andreuses, familiar desktop e-mail clients and directoryapplications such as the Microsoft Outlook Client,the Lotus Notes Clients, Active Directory, and IBMLotus Address Books.

Rich Media Communications—IntegratedAudio, Video, and Web Conferencing

Rich Media Conferencing is an extension of IP AudioConferencing. However, it also provides the integra-tion of rich media applications—voice, web, videoconferencing, instant messaging and presence serv-ices, as well as document sharing and desktop shar-ing to support collaboration, meetings, lectures, vir-tual teams, webinars, and conferences.

Like it's counterpart IP Audio Conferencing, the ben-efits of using secure on-net Rich MediaConferencing resources saves significant capital andoperating expenses over using alternative legacyvoice conferencing equipment and separate servicesof web and audio and video that is connected withTDM equipment and legacy voice circuits.

Rich Media Conferencing services can be locatedanywhere on the network, and can use existing IP con-verged network bandwidth, as opposed to expensivestand-alone voice circuits to support the conferencingservice, including the ports and cards to connect,support and terminate Rich Media Conference calls.

IP based Rich Media Conferencing services cansupport ad-hoc reservation-less or scheduled con-ferences and easily integrate with TDM voice PBXequipment to provide these services to existing PBXor service provider environments where needed.Services of Rich Media Conferencing can beaccessed from IP phones, desktops, or from legacyvoice terminals and desktop web browsers. It is notrequired that web-audio and video services be usedon any given conferencing call. It is also not requiredthat services for desktop, application, or documentsharing are used on any given conference call. InRich Media Conferences, participants see eachother, see who is attending, see who talking, can par-ticipate in text chat with each other; can easilyschedule these conferences from existing e-mail,calendaring, or Instant Messaging client tools; canparticipate and collaborate in shared workspaces;can have breakout sessions; and can control theinteraction of the virtual meeting, including the abilityto automatically record and play back meetings.


Rich Media Conferencing provides significant pro-ductivity benefits to the organization to the degreethat resources are made easily available and acces-sible to employees. With IP, the costs of these serv-ices after initially deployed are relatively small whenreusing the converged IP Communications network.

IP Videoconferencing

Three additional IP Communications services thatfurther extend the capabilities of an IPCommunications environment include IPVideoconferencing, Video Telephony, and streamingcommunications services such as video-on-demandand streaming audio-on-demand.

IP Videoconferencing provides an organization withthe ability to use real-time, two-way, or multi-party,multi-site video conferencing services using H.323protocols over a packet network. The advantages ofusing IP Videoconferencing are flexibility, higherquality, greater availability and reliability, and muchlower equipment and operating cost over traditionalISDN videoconferencing network technologies andservices. Because IP Videoconferences can takeadvantage of existing data networks and lower costH.323 endpoints and equipment, IP videoconferenc-ing can support a greater number of users and moreflexibly with desktop or dedicated videoconferencingterminals. IP Videoconferencing solutions also inte-grate with and interoperate with existing H.320(ISDN) videoconferencing systems and endpoints,using H.323 to H.320 gateways where needed. Thisallows anyone using any type of technology to easi-ly participate in IP Videoconferencing calls.

Because IP Videoconferencing systems are muchless expense to deploy and operate, they provide avery flexible and economical way for an enterprise tovideo-enable its infrastructure. Videoconferencingsystems must be designed carefully, however, due tothe higher bandwidth requirements that video servic-es typically place on a network, and also take intoaccount whether conference calls are using lecturemodel / broadcast style, or many-to-many style com-munications. The issues of how voice and video traf-fic are handled over the network with intelligent net-working protocols such as multicast, RSVP, call

admission controls, and dial plans using gatekeep-ers, switches and routers in the network are alsoimportant. The services of IP Videoconferencing areflexible and can be extended easily to accommodatenew locations as needed. IP Videoconferencing sys-tems are generally comprised of gateways, video-conferencing bridges, gatekeepers and endpoints, inaddition to the converged network.

IP Video Telephony

IP Video Telephony extends the integration capabili-ties of an IP Communication environment by provid-ing integrated video with voice technologies thatautomatically use IP Videoconferencing services forconverged desktop video endpoints, integrated videoendpoints, or H.323 video endpoints, as needed. Forexample, with video telephony, video is just a phonecall. Video is available with every phone call, and ad-hoc videoconferencing at the touch of a button isavailable for every phone call. In other words, thelevel of integration is much higher with video teleph-ony that automates the usage and user experiencewith video telephony features being automaticallyprovided by the underlying IP Videoconferencingresources.

Extension Mobility

Extension mobility allows users to log into any IPPhone and receive their own phone numbers andprivileges at that location. Extension mobility is oftencalled hoteling or hot-desking. When used togetherwith softphones, employees also have the ability touse VPN technologies and PC desktops or laptops togain access to corporate communications.

Because extension mobility allows one IP phone tobe shared among many workers when in the office,it can consolidate and reduce or eliminate the needfor facilities workspace, saving real estate and facili-ties costs.

Unlike traditional PBX systems, IP phones supportplug and play moves/adds/changes that allows usersto take their IP Phones to new locations, plug them


into the Ethernet jack, and have all user privilegesand settings re-established when the phone is regis-tered on the network. This reduces administrativecosts and service interruptions that are generallyexperienced during moves. One additional advan-tage of converged IP Phones is that certain modelscan also support the IP Phone device and the desk-top using a single Ethernet drop (one jack) for bothIP phone and the PC desktop while still providing thetreatment of switched (segmented) data traffic needsof 10/100 to the desktop.

IP Telephony Applications

Ease of deploying new web-based communicationservices that can be integrated with existing sys-tems, databases, or third party tools easily andquickly is an additional advantage of an IPCommunications system. By using standardizeddevelopment application programming interfaces(APIs) and standardized web development technolo-gies such as extensible markup language (XML),hypertext transport protocol (HTTP), JAVA, JavaTelephony Application Programming Interface(JTAPI), and Telephony Application ProgrammingInterface (TAPI), organizations can more quickly,easily, and cost effectively deliver ComputerTelephony Integration (CTI) applications and desktopintegration. Applications can be customized to sup-port the process and workflow needs of a specificworkgroup or department and be deployed as hori-zontal enterprise-wide applications. Examplesinclude applications such as inventory management,medical transcription, executive information, timecard applications, bulletins, HR functions, notifica-tions, broadcasts, and alerting.

Applications can be provided so that an IP phonedoubles as a kiosk for customer service operations inretail environments, such as reaching customer serv-ices, accessing local events, or purchasing ticketson-line more easily and quickly.

The key point is that with IP Communications, the IPphone supports more than just voice. It can also sup-port a wide variety of open desktop and IP phoneapplications available from third parties, or those thatcan be developed by the customer, and managed,

delivered and accessed from anywhere in the IPCommunications environment. Such applicationswould include:

� Videoconferencing (wired and wireless)� Instant messaging (wired and wireless)� Whiteboarding—An area on a display screen

that multiple users can write or draw on,enabling visual as well as audio communication.

� Collaborative browsing (also known as co-browsing)—A software-enabled technique thatallows an employee to interact with a customeror another employee by using their Webbrowser (controlling it remotely) to show themsomething.

� Call forwarding and intermittent call transfer—Allows for the transfer of calls to the telework-er's cell and home phones.

� Enhanced Web Surfing—Integrating phonenumbers embedded in Web pages with a soft-ware-based phone so you can click on and dialany phone number you see while surfing theWeb.

� Interactive Voice Response (IVR) applicationsfor constituents.

� Audible E-Mail—Text-to-speech capability forretrieving e-mail by phone.

� Call routing—Involves the routing of calls usingrules-based call handling, e.g., you can havecalls go to your voice mail during a meetingand have them sent to your cell phone in theafternoon.

Mobility Applications

Softphones/Soft-agentsSoftphones/soft-agents (Customer Agent Desktops)can be used from any laptop or PC workstation con-nected to the IP Communications environment.Combined with VPN technologies or soft VPN clientsand soft-tokens, softphones provide a very costeffective solution for support of mobile teleworkersand for telecommuting applications. Voice, video,and data services can be accessed from remoteoffices, home offices, hotel rooms, and internationalor domestic locations to avoid international and tollcosts. Softphones also support corporate directories,or personal address books that can be stored on


network servers, or on the local desktop machine.The advantages of deploying softphone and soft-clients further extends the power and productivitybenefits of an IP Communications environment byallowing workers to expand their zone of productivityand ease of access to communication services.

In the case of soft-agents, with IP Contact Centerapplications, it provides for the ability to locateagents anywhere on a converged network, out-source operations, and save on real estate costs, inaddition to the benefits of achieving continuous inno-vation in the communication application because it issoftware rather than hardware based. Lastly itallows organizations to reuse and leverage theirexisting resources and assets in desktop and con-verged networks.

802.11a/b/g Wireless LANs and Wireless or SoftIP PhonesOn average, according to a study conducted by NOPWorld Technology, wireless LANs enable users to beconnected to network resources 1.75 additional hoursper day, which translates into the average user beingas much as 22 percent more productive. Given areported average salary of $64,000 for a professionalworker, this indicates that the annual productivityimprovement per user is worth, on average, $7,000.

For a modest cost ($300 to $500 per person, or $1 to$2 / per person / per day, including equipment, instal-lation, training, and annual support), organizationscan extend their existing wired networks to locallymobile professionals in a campus setting using wire-less LANs. The wireless network extensions havecomparable speeds to the very high speeds of thewired network, making the wireless LAN basically anequivalent, portable version of the enterprise net-work. By extending the worker's productivity zone,wireless networks protect organizational investmentsin existing wired networks because those networksbecome accessible to greater numbers of users formore of the time.

These benefits are further amplified by the fact that40 percent of enterprise class laptop computers nowship with wireless LAN capabilities already included.Although there were approximately 2,000 wirelessLAN hot spots in the United States in early 2005, this

number is expected to grow to at least 6,000 by theend of 2006, according to Gartner.

In short, wireless LANs will further extend the bene-fits of IP Communications by increasing the zone ofproductivity in terms of ability to access corporatedata and communications resources and support themobile professional with:

� Increased productivity;� Increased responsiveness;� Improved business resilience; and,� Increased utilization of IP Communications and

technology assets.

Now that wireless LAN standards have matured andimportant security enhancements have been addedto them, a wireless LAN user's flexibility to stay on topof communications throughout the workday ratherthan waiting till 5 p.m. to deal with a day's worth ofmessages could supply a colleague or a constituentwith vital information in time to complete a transac-tion or avoid some unnecessary delay. Multiply thisby hundreds or thousands of workers across anorganization, and the payoff adds up quickly.

Teleworker / SupportOrganizations are constantly striving to reduce costs,improve employee productivity, and keep employeeswithin the organization. These goals can be fur-thered by providing employees the ability to workfrom home with similar quality, function, perform-ance, convenience, and security as are available inthe office. Employees who are occasional or full-timeteleworkers require less office space. By providing awork environment in the residence, employees canoptimally manage their work schedules, allowing forhigher productivity (less affected by office distrac-tions) and greater job satisfaction (flexibility in sched-ule). This transparent extension of the enterprise toemployee homes is meeting the objective of a robustteleworker solution. The capabilities further extendIP communications network capabilities by providingIP mobile access for vehicles and people in the field(e.g., state patrol, case workers, etc).

To summarize the benefits of the teleworker voiceand data solution, this solution extends the advan-tages of VPNs (e.g. cost savings, data application


support, extended availability, security, and privacy)to provide secure enterprise voice services to full-time and part-time teleworkers.

Extended IP Communications Applications

Emergency Alerting ApplicationsMany state and local governments are gaining sig-nificant value from applications such as Berbee'sInformacast emergency alerting application, andsimilar third party XML broadcast applications thatcan provide immediate broadcast alerting functionsto all government offices using open IP alerting func-tions that have been integrated with the IPCommunications system. These applications cansupport scheduled broadcasts, alerts, and bulletinsor ad-hoc emergency alerts throughout all emer-gency responder and state, local, and city govern-ment offices using IP networking technologies.Unlike TDM technologies, alerts can be customized,including visual and verbal system-wide or grouppaging functions to ensure fast and effective home-land security and emergency alerting services aredelivered throughout a community or jurisdiction.

Business Continuity / Disaster Recovery

Land and Mobile Radio ConvergenceLand mobile radio convergence provides for the con-solidation, integrated management and communica-tions across heretofore separate, disparate and iso-lated radio and legacy voice technologies that pro-vide for emergency fire, police, and marine radioservices. IP Communications and IP Multicast net-working technologies allow for the cost effective con-vergence of these legacy radio technologies, and forstreamlined process convergence to improve coordi-nation between agencies. By using IP applicationsand networking services to converge and combinethese radio networks onto one more logical IPConferencing bridge, advance coordination, monitor-ing, receive only, and/or transmit services can beprovided for ad-hoc, meet-me, and scheduled IPconferencing services.

These services use IP media streaming services and

H.323 standards to support interaction betweenexisting analog, digital voice technologies, and dis-parate radio systems that can be integrated within anIP Telephony communications environment using IPphones and desktop applications. The ability of IPprotocols to span geographies and connect commu-nication independent of physical limitation on specif-ic hardware enables improved flexibility and scalabil-ity to support convergence of communication servic-es using disparate legacy technologies.

N11 Services—211, 311, 511, 711 Services toRelieve Overburdened 911 SystemsThe unique benefits of IP Contact Center technolo-gies and applications to combine voice, data, web,and e-mail traffic of client requests from varioussources can facilitate and streamline the deliveryand implementation of shared e-government serviceportals, thereby streamlining the number of govern-mental employees required to support N11 services,while providing higher levels of flexibility andautomation for these services.

Video/Audio-On-Demand, E-LearningVideo-on-Demand and Audio-on-Demand are usedto provide training to employees using e-learningand streaming video-on-demand network servicesdeployed on the IP Communications network infra-structure. The value of these services is that theycan be deployed anywhere on the IP converged net-work to support e-learning, training, staff develop-ment activities, and knowledge management for theorganization. Streaming IP services can be deliveredto IP endpoints and desktops that support standardstreaming and Windows Media Player protocols.

IP Telephony Implementation Considerations

If you implement IP Telephony, you will still need toconnect to the PSTN for certain services and to haveaccess to phones that are not part of your IP teleph-ony deployment. As mentioned earlier, the PSTNsupports a variety of voice services through the sig-naling control points. An Internet telephony devicewanting to connect with one of these services mustuse PSTN signaling for the foreseeable future. This,and the need to connect to PSTN customers, leadsto a hybrid PSTN/VoIP configuration. (See Figure 5.)


In considering the adoption of IP Telephony, you maychoose an incremental implementation approach fora variety of reasons. The implementation can bephased to coincide with the termination of equipment

leases or service agreements. There may also bedrivers for the IP implementation that would prioritizeIP telephony for certain work groups or locations(e.g. call centers or remote offices). (See Figure 6.)

Figure 5. Hybrid PSTN/VoIP Configuration

Figure 6. Reasons for Hybrid PBX Adoption

Source: www.voip-info.org


19

A "Typical" VoIP Configuration

A typical VoIP system consists of a number of differ-ent components:

� Gateway/Media Gateway� Gatekeeper� Call agent� Media Gateway Controller� Signaling Gateway and a Call manager

The gateway converts media (e.g. voice, video) pro-vided from one type of network to the format requiredfor another type of network. For example, a gatewaycould terminate bearer channels from a switched cir-cuit network (e.g. DS0s) and media streams from apacket network (e.g. RTP streams in an IP network).This gateway may be capable of processing audio,video and T.1201 alone or in any combination, and iscapable of full duplex media translations. The gate-

way may also play audio/video messages and per-forms other Interactive Voice Response (IVR) func-tions, or may perform media conferencing. The callcontrol "intelligence" is outside the media gatewaysand is handled by media gateway controllers (alsocalled call agents). These elements synchronize withone another to send coherent commands to themedia gateways under their control. A control proto-col is used to control VoIP gateways from the exter-nal call agents. (See Figure 7.)

A media control protocol is implemented as a set oftransactions composed of commands. The call agentmay send commands to gateways that create, mod-ify, and delete connections, or that create notificationrequests and auditing commands. Gateways maysend notification and restart commands to the callagent. All commands include text-based headerinformation followed by (optionally) text-based ses-sion description information.

Figure 7. Simple VoIP Configuration

1 T.120 supports multiple users in conferencing sessions over different types of networks and connections.




Selecting the Right Products for InvestmentProtection and On-Going Management

In migrating to IP telephony, one of the larger issuesin selecting a vendor would have to be investmentprotection and upgradeability. It is important to knowwhere products purchased are in their lifecycle andthe future path for upgrades and growth. Past per-formance is generally indicative of future activity,unless the future product plans are explicitly stated.Be aware of the vendor's on-going support for exist-ing products. How long will products of this scale besupported by each vendor being considered? Havethey traditionally been upgradeable with minimal (orwith any) hardware and/or software, or is theupgrade path a complete replacement? Related tothis issue is the frequency of maintenance upgrades.This can be a double-edged sword, as new featuresand functions are nice, but doing large scaleupgrades frequently can be troublesome for the staffas well as the end users. How much testing is donebefore maintenance releases are issued?Understanding any potential changes in how the net-work will react is imperative to adequately providinginformation to the users affected.

Another consideration is the maintenance contractitself. How long are maintenance releases, andmaintenance calls in general, and are they includedat no cost after the initial purchase? If it is determinedto be the best path, can the maintenance function bebrought in-house? What implications will this have onthe contract for maintenance releases and releasesinvolving added features or functionality? Fullyunderstanding future direction following deploymentmay aid in determining the right equipment provider.

The individuals managing the network will needaccess to reports ranging from the standard voicereports covering traffic patterns, trunk usage, etc., tothe IP reports covering dropped cells and trunk uti-lization. The reports necessary to manage the VoIPnetwork will be similar to the reports in use today formonitoring the voice network, though there will be

additional reporting criteria in addition to the tradi-tional voice reports that are required to adequatelymanage the network. All of the reports will have to becreated, as the sources for the information will beentirely different. It is imperative these reportingcapabilities are available when the system isdeployed to aid in trouble avoidance and resolution.

The Business Case for IP Communications—Return on Investment (ROI) and Total Cost ofOwnership (TCO)

Because a VoIP migration project may come underconsiderable internal and public scrutiny and through-out its three to five year evolution as new services areadded, it is important to put in place some basic met-rics that will be used to communicate and measure thesuccess of convergence initiatives over the migrationtimeframe, and beyond. Ideally, these will be outlinedand described at appropriate levels for executive,management and constituents, to describe the valueof a converged communication system in terms ofwhat it provides for the organization.

Because converged IP Communications networksprovide capabilities that can be used by many com-munications applications including data, voice,video, wireless and application systems, it createsmany synergies to achieve measurable benefits. Forexample, with common network infrastructure, end-to-end security management needs, mobility needs,and new productivity applications can be more easi-ly added and extended to the workforce. Knowingservices are deployed from a baseline, in terms ofwhat capabilities exist, their ongoing costs, how diffi-cult to expand, change or grow, and their impacts onstaffing, labor, workflow and process can set thestage for useful metrics and a plan that clearly alignswith key priorities and transformational objectives.

Some categories of metrics and ROI areas to look atwhen considering the use of new technologies, usingIP communications technologies include the following:

the economics of VoIP


� Cost reductions;� Centralization of services;� Reduction of infrastructure;� Reduction in cost of PSTN services;� Administration of Moves/Adds/Changes (MACs);� Remote Administration;� Interoperability;� Productivity improvements;� Investment Protection with reuse, extension,

evolution of intelligent converged network andapplications; and,

� Optimized staff (consolidated telecommunica-tions staff, reduction in training required overthe long term).

A single converged infrastructure incorporates com-mon resources for security, resiliency, multiple con-verged applications, and converged communica-tions. This can create multiple logical networks onthe single network. IP communications also providesthe ability to use carrier based transport for state andlocal governments to create their own transport net-

work using technologies such as metro-Ethernet orusing available dark fiber that is typically stateowned. The addition of optical network capacity andservices to use these assets can translate to signifi-cant savings and benefits in terms of a state's abilityto deliver a broad range of services and new appli-cations over time.

There are also anticipated savings from:� Using a common unified security / manage-

ment infrastructure.� The ability to more easily gain new technology

features, which are more simple and lessexpensive (than PBX technologies) for soft-ware upgrades and the type, range, richness,and economy of applications deployed.

� Productivity improvements that can be meas-ured in terms of FTE hours, labor and staffingcosts, and workforce productivity benchmarks.

For the average payback of VoIP by vertical industry,(See Figure 8.)

Figure 8. Average Payback of VoIP by Vertical Industry

Source: Cisco Network Investment Calculator (CNIC), March 05


The delivery of IP communications productivity appli-cations and support for collaboration, rich-media,teamwork, unified messaging, mobility, wireless, andteleworkers reduces costs and supports a more dis-tributed, effective workforce. While this is well docu-mented in the industry, specific metrics for any givenproject or initiative must be established. The metricsmust be reasonable, valid, and accepted by all keystakeholders for the results being sought.

The benefit of IP communications can be realizedwhen any of the following organizational scenariosexist:

� Maintaining multiple equipment, personnel,and budget for multiple networks (e.g. voiceand data).

� Existence of many branch offices, especiallyinternational sites, where traditional PBXinstallations and toll fees can be expensive.

� Undergoing change through growth or aplanned move to new physical office space,where PBX installations are costly and hook-uptime is critical.

� Reliability and durability of communication isrequired in case of emergency situations. IPwas designed with this in mind, whereas whena destroyed or damaged PBX will sever com-munication.

� Heavy call center usage that may benefit fromIP Contact Centers to streamline operations,increase customer satisfaction, and tie togeth-er web and back-end systems.

� Need to quickly update employees with criticalinformation in a more efficient manner.

� Deploying an IP communications applicationsuch as unified messaging, rich media confer-encing (audio, web, video), wireless, supportfor mobility, teleworkers, telecommuting.

There are several ROI metrics that can be capturedeffectively once a baseline is established. This willprovide measurements prior to, during, and periodi-cally throughout a migration to IP communications.They are:

Savings from Reduced Network InfrastructureCosts

� Expense for new sites.

� Remote site network equipment.� Equipment upgrade and replacement cost.� Ethernet wiring drops: an IP Phone and PC

share a single jack.� International and domestic interoffice call

charges.� Number of external communication lines,

especially to the public switched telephonenetwork (PSTN).

Savings from Improved Administrative andOperational Costs

� Improved productivity of network support staff.For example, unified messaging increasesemployee productivity by allowing users toaccess voice mail from their PC and e-mailmessages from their IP phone. Independentstudies demonstrate that employees save 20to 40 minutes per day processing messagesversus managing two separate systems.

� Ten to forty percent productivity improvementafter convergence.

� Shift staff focus from administration to value-added projects that leverage expertise.

� Consolidated help desk.� The cost of moves/adds/changes is significant-

ly reduced from $75 to $125 each.� Onsite support and maintenance contracts.� Centralized call processing reduces branch

office administration expense.� Ongoing network design, project management,

and implementation.� 80 percent of large enterprises view the

deployment of IP-enabled, integrated contactcenters as a key converged application.

Maturing VoIP standards and technology are makingthe concept of deploying converged infrastructuresmuch more viable. When making the decisions toimplement VoIP transport and/or IP Telephony, it ishelpful to understand the drivers associated witheach and the experiences of similar organizations.

The typical VoIP Savings include:� Elimination or reduction of PSTN toll charges.� Elimination or reduction of service and support

contracts on existing PBX hardware.


� Elimination of the requirements for Centrexservices and charges.

� Collapsing voice and data infrastructures sup-port, and management resources into one con-verged network to reduce the need for staff,maintenance, and upgrades and realize areduction in the costs associated withmoves/adds/changes.

� Reduction in the on-going costs for the supportand maintenance of separate voice messagingsystems.

� Improved productivity for remote and mobileworkers by extending the enterprise to them(e.g. providing them with the same integratedcapabilities as office workers) from any placeon the Internet.

The experience of previous deployments indicatesfour major sources of savings from VoIP and IPTelephony implementations. (See Figure 9.)

Wholesale replacement of PBXs is extremely rare. Itis much more common to see federated decisionmodels in organizations with political subdivisions,segmented funding streams, and dispersed geogra-phies. Finding the balance is the goal here.

Many enterprises with voice and data convergenceprojects underway are consolidating voice and datastaff, usually under a CIO. This trend has proven tobe the most difficult culturally, but also is the mostrewarding from a business standpoint. CIOs must becreative as they assimilate teams. Research showsa converged staff creates its own culture and willconsider a variety of resolutions to a business prob-lem, regardless of the incumbent technology vendor,as opposed to being convinced that the next releaseof "product X" will solve it. As a result, convergedstaffs tend to be more business-solutions-orientedand regard technology as a tool to accomplish this.

Figure 9. Sources of Savings from VoIP and IP Telephony Implementations

Source: Cisco Network Investment Calculator (CNIC)


The amount and type of IP Telephony products andservices will be unique to an organization's currenttelephony configuration and future needs. Additionally,there are multiple configurations for connecting IPphones to the network. (See Figure 10.)

Converged networks extend IP networks to leveragea common infrastructure for voice, video, data and allother converged communications. Major telephonyequipment vendors have stable IP-based solutionsto complement their traditional TDM voice switchinggear. Network infrastructure vendors have optimizedtheir products specifically for converged applications

and are working closely with application vendors tofully exploit the underlying intelligence in the net-work. Organizations have a choice of proven solu-tions and are not locked into a single vendor for ahighly functional end-to-end solution. The movetoward a converged communication infrastructureshould be incremental and protect investments inexisting legacy infrastructure to ensure a smooth,low risk transition.

Voice traffic is converted to IP telephony packets bydifferent devices, depending on the architecture ofthe solution. In toll bypass applications, gateways

VoIP implementation and planning

Figure 10. Connectivity Options



convert voice between the PBX and IP network. Inmost IP telephony deployments, packet conversionoccurs at the IP phone as well. In the case of archi-tectures involving analog phones and phone hubs,IP telephony conversion occurs at the phone hub.Most IP phones use industry standard protocols suchas SIP or H.323 to communicate with other IPdevices. However, similar to TDM-based PBX andcertain proprietary handsets, not all IP phones willwork with just any vendors' IP call manager due toproprietary client/server protocols.

For an organization that is considering voice anddata convergence, putting IP telephony on the WANis as important as IP telephony on the LAN. IP teleph-ony on the WAN is where the advantages of tollbypass become evident. The reasons for this are pri-marily economical. Cost savings can be immediatewhen long distance phone calls are diverted fromPSTN and sent over an existing IP-based WAN.Implementing an IP telephony infrastructure needs to

be an evolutionary step with proper consideration forlegacy TDM PBX systems and adequate planning.The total planning time is entirely dependent on thesize and complexity of deployment. The individualplanning considerations and average percentage oftime spent on each aspect of planning are repre-sented below. (See Figure 11.)

Centrex Replacement

There are numerous examples and tools available tohelp justify the cost savings of moving from Centrex.In general, most customers can achieve significantcost savings and additional ROI benefits from superiortelephony services, higher productivity and greaterflexibility and resiliency with IP Communications.Savings of 30 percent to 50 percent or higher, withpayback periods averaging 48 months or less, arecommon. Examples of recent deployments and ROIinclude:

Figure 11. IP Telephony Planning Estimates



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� City of Southfield—Case Studyhttp://newsroom.cisco.com/dlls/ts_120303.html

Common Centrex Migration ConcernsOnce customers have decided to deploy IPCommunications solutions, careful considerationsmust be given to how the migration will take place. Akey consideration for most large implementations(e.g. greater than 200 phones) is that a flash cut isnot practical—the organization must plan on migrat-ing to IP Communications over time.

Migration planning will involve the need to supportthe Centrex service and any legacy voice equipmentas well as the IP Communications solution during themigration period. The management and planning formigration and operations within a hybrid environ-ment will involve additional steps and considerations.Planning should also take into account that there willbe a mix of Centrex users that are unaware whichother users have migrated to IP Telephony. To pro-vide an overall user experience that is as seamlessas possible, the issues of interoperability and featuretransparency between the Centrex environment, thelegacy PBX voice equipment and the IPCommunications system needs to be carefully con-sidered, with people, processes, and project man-agement that ensures a successful transition.

In a mixed or hybrid telephony environment involvingCentrex and IP Communications equipment, the fol-lowing list of features can be used as a high levelchecklist for features that should be supportedbetween IP phones, between IP phones and Centrexphones, and between IP phones and the PSTN.

� Basic telephony features, dial tone, dial-tonemulti-frequency (DTMF), multiple lines, hold,call transfer, call conference (ad hoc).

� Retaining telephone numbers on the Centrex

service and porting these to the new IP phonewith Direct Inward Dial numbers.

� Replicating Centrex dial plans, if standardized.� Ability to support 4 or 5 digit dial plans.� Ability to support IP phone to Centrex phone

using existing 4 or 5 digit dial plan.� Ability to support Centrex phone to IP phone

using existing 4 or 5 digit dial plan.� Ability to support local calling: 9 plus 7 or 10

digit.� Ability to support long distance calling using 9-

1 plus 10 digits or 8-1 plus 10 digits or 1 plus10 digits.

� Calling number display between IP phones andCentrex.

� Calling name display between IP phones andCentrex.

� Speed dials (system and personal).� Intercom features.� Ring again.� Uniform Call Distribution (UCD) hunt groups.� Automatic Call Distribution (ACD) queues.� Voice mail integration.� Existing voice mail box preferred.� Ability to support voice mail networking.

Centrex customers can acquire an ISDN primaryrate interface, a Channel Associated Signaling(CAS) T1 service or analog direct inward dial (DID)trunk along with new DID phone number extensions.(Note: CAS is the transmission of signaling informa-tion within the information band, or in-band signaling.This means that voice signals travel on the same cir-cuits as line status, address, and alerting signals. Asthere are twenty-four channels on a full T1 line, CASinterleaves signaling packets within voice packets.Therefore, there are a full twenty-four channels touse for voice.) These new telephone numbers or DIDnumbers would preferably be from the sameexchange as Centrex, but it is not mandatory. Thenew trunks connect to the appropriate gateway thatprovides PSTN connectivity for the IPCommunications solution, as well as calling numberand name display support between the PTSN andCentrex service and the IP telephony environment.Voice mail and unified messaging requirements canbe supported with interoperability supported for

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SMDI integration, and for using one of the followingtechnologies to integrate with the customer's existingvoicemail system or with a Centrex Central Officebased voicemail:

� Audio Messaging Interchange Specification—Analog (AMIS-A): This is a standard analogvoice message networking method that relieson telephone channels for connection.

� Voice Profile for Internet Mail (VPIM)—VPIMbrings voice and fax into the realm of Internetmessaging technology, allowing Internet mailfacilities to include voice and fax messageexchanges.

� Digital Bridge—A device that connects andpasses packets between two network seg-ments that use the same communications pro-tocol.

There is typically a per transaction cost for theseservices and it requires certification testing for eachinstall with the carrier. This is important since the car-rier generally will not allow non-Centrex lines to haveCentrex Central Office voicemail boxes. Should thecustomer wish to keep their existing voice mailaccount, an SMDI connection will be requiredbetween the IP Communications system and theexisting voice mail system.

Considerations for CentrexWhile Centrex in the past has been an attractiveoption for telecom needs, the typical customer has todeal with the following on-going challenges:

� High monthly operational costs: Centrexinvolves tariffed monthly charges per phonewhich may include Centrex line, PSTN, phonefeature charges, voice mail, moves/adds/changes, 911, and possibly handset lease orrental costs. These rates vary depending onoptions, contract term, and size of install.

� Increasing costs of Centrex: While the costof IP Communications ownership hasdecreased over the past few years, Centrexprices are going up in many areas.

� Not universally available: Centrex availabilityis very much tied to whether it is available onthe Central Office switch serving the customersite. Very often a customer within a single city

or region may find that only some of theiroffices have access to Centrex, meaning thatother offices have to install key systems, PBXsor business lines. This means multiple types ofsystems to support and different feature setsfor different offices.

� Lack of a coordinated dial plan: Customersthat have a hybrid of Centrex and key systemsoften suffer from not having a coordinated citywide 4 or 5 digit dial plan. This means sites notserved by Centrex often have to dial seven orten digits to call non-Centrex sites and vice-versa. Some key systems are sophisticatedenough to perform digit manipulation to hidethis fact from the end-user.

� Dissimilar unlinked voice mail systems: Apotential issue with a mix of Centrex and keysystems is that the users would often have dif-ferent voicemail systems with different userinterfaces and no ability to transfer messagesbetween sites.

� Cost and lead-times of moves, adds, andchanges (MACs): The largest cost and loud-est customer complaints often surround MACs.Lead-times can be five or more days and sam-ple costs run anywhere from $50 to $150 perMAC, often with a minimum charge per visit.Many organizations average one to two MACsper employee annually, at considerableexpense.

� Lack of control and speed over new featuredeployment: Centrex customers have to dealwith very few innovations and very slowdeployment of new features based on the real-ity that a central office switch supporting tensof thousands of customers cannot be changedoften. Customers also have no control overwhen switch upgrades would happen meaningthat a switch upgrade could happen in theirmost critical time (e.g. year end, election time,start of legislative session).

� Feature charges: While a Centrex line chargeprovides dial-tone and basic features, carriersoften charge extra money for features.Examples include shared line appearances,second number appearances on a set, namedisplay, music on hold groups, and huntgroups. These often average out to several


dollars per month per user but aggregate tolarge amounts of money across an organiza-tion. These charges can be reduced or elimi-nated with an IP telephony implementation.

VoIP Support for Persons with Disabilities

VoIP-based applications can also be a promisingtechnology for people with disabilities. VoIP inte-grates the phone, voice mail, audio conferencing, e-mail, instant messaging, and Web applications likeMicrosoft Outlook on one secure, seamless network.Workers can use their PC, laptop, or handheld as aVoIP phone from virtually anywhere, with the samephone number, which benefits telecommuters,including those whose mobility is impaired and mustwork from home.

The biggest advantage for supporting the physicallychallenged is that everything can be accessedthrough voice, audio, or a combination of both.Hearing impaired employees can place or receiveTTY-compatible calls from their computer without theneed for a legacy TTY device. TTY, which uses tonesto transmit typed conversations over phone wires, isnow the main form of phone communication for thehearing and speech-impaired. In fact, one of theimplementation issues in IP telephony may be theability to support TTY functionality for employeeswith such devices.

With VoIP-enabled applications, hearing impairedworkers can read their voice mail from their e-mailprogram in a fraction of the time it takes with a TTY,which operates at a slow 45 baud per second. Visionimpaired workers can use a Windows-based appli-cation called a softphone in conjunction with an IPphone to hear audible caller ID, a missed-call log,and line status without the need to memorize or markbuttons on the phone.

Managers should think of VoIP as empowering work-ers with disabilities to perform their jobs better.However, setting up VoIP to use assistive-technolo-gy software is not necessarily a snap. Just being atechnically savvy employee might not be enough. Itoften takes a trained telecom or information-technol-ogy manager to assemble a VoIP system for workerswith individualized assistive needs.

Fortunately, some VoIP providers understand thisand are working with third-party vendors to createaccessible solutions. VoIP is based on open stan-dards, which make it possible for assistive technolo-gy to work with IP software. An application at theU.S. Commerce Department dubbed "Informacast,"supports an emergency-broadcast system. The toolsimultaneously sends audio streams and text mes-sages to multiple IP phones so that hearing andvision impaired workers will not miss importantalerts, like fire alarms.

Manufacturers and access providers need to shapethe infrastructure to make VoIP perform for thosewhose vision or hearing is impaired as well as it doesfor others. Then, vision and hearing impaired work-ers can experience what everyone else does: ubiq-uitous access to information, and finally, a functionaloption for screening their calls.

Regardless of which deployment model is chosen,the design of the IP Telephony network shouldensure that telephony features are more accessibleto users with disabilities, in conformance withSection 255 of the Telecommunications Act and 29U.S.C. 794 Section 508. IP Communications canprovide superior capabilities to provide system wideaccessibility to users with disabilities because it sup-ports unified messaging, additional desktop tools,and web based portals for facilitating communica-tions to not only a few users who have special equip-ment provisioned, but for everyone on the systemwithout significant additional cost.

Figure 12. Jitter

Source: www.Voiptroubleshooter.com


Network Infrastructure—AdvancedIntelligent Network Features

A converged network requires a complete set of toolsand integrated technologies for deploying and man-aging network service that support IPCommunication services. These tools are used toprovide end-to-end QoS for voice, video, data, andwireless applications, to ensure security and man-ageability, and to minimize network costs with sup-port for resiliency and flexibility in layer 2 and layer 3protocols and services that enable converged IPCommunications services to work together withother network applications. Today's converged net-work technologies primarily consists of high speedlayer 2 and layer 3 10/100/1000 switched networksand high-performance gigabit or terabit integratedswitching and routing platforms. The design of con-verged networks has recently become more auto-mated with sophisticated automation technologies tostreamline the deployment of these requirementsusing auto-QoS and self-defending networking tech-nologies, as well as improved management tools.

Cabling

Although IP Communications services can bedeployed over Category 3 wiring, a minimumrequirement of Category 5E or above is recommend-ed, since Category 5E wiring is a voice and datagrade cable and has also been tested for GigabitEthernet. Category 5 wiring can also be used, but isless preferred; Category 6, the newest standard forcabling, can be used, but is not required. Generally IPTelephony and related IP Communications applica-tions use a single Ethernet drop deployment model.This means that a single Ethernet port provides fordesktop and IP phone support from a single outletjack. In-line power is delivered to the IP phone, whilea switch port in the IP phone allows data traffic to belogically and physically separated from the voice traf-fic, yet still support the desktop.

Network Infrastructure

IP telephony places strict requirements on IP packetloss, packet delay, and delay variation (or jitter). (SeeFigure 12.) Therefore, IP Telephony requires QoS

VoIP implementation technical considerations


mechanisms available from switches and routersthroughout the network. For the same reasons,redundant devices and network links that providequick convergence after network failures or topologychanges are also important to ensure a highly avail-able infrastructure for LAN, WAN, and the wirelessnetwork infrastructure.

LAN Network Design

Properly designing a LAN requires building a robustand redundant network from the top down. By struc-turing the LAN as a layered model using core, distri-bution and access layers that are typically used fordesigning campus networks, a highly available, faulttolerant, and redundant network can be designed.

Power over Ethernet (PoE)

PoE (or inline power), although not a strict require-ment for IP Phone deployments, is highly recom-mended due to the network and administrative sim-plifications resulting for IP Phones and for otherdevices such as wireless access points, IP videocameras, and other IP devices supporting IEEE"802.3af" power standards.

PoE is 48 volt DC power provided over standardEthernet unshielded twisted-pair (UTP) cable.Instead of using wall power, IP phones and otherinline powered devices (PDs) such as WirelessAccess Points can receive power provided by inlinepower-capable switches or other inline power sourceequipment (PSE). Inline power is enabled by defaulton all inline power-capable switches.

Deploying inline power-capable switches with unin-terruptible power supplies (UPS) ensures that IPphones continue to receive power during generalpower failures. Provided the rest of the telephonynetwork is available during these periods of powerfailure, IP phones will be able to continue making

and receiving calls. Inline power-capable switchesare deployed at the campus access layer withinwiring closets to provide inline-powered Ethernetports for IP phones, thus eliminating the need for wallpower.

The use of Category 3 cabling is supported for IPCommunications under the following conditions:

� The access layer switch port must either sup-port 10 Mb only or be hard-coded to 10 Mb.When hard-coding switch ports to 10 Mb, it isalso recommended that the port be set to fullduplex.

� All devices plugged into the IP phone PC portshould be configured manually to 10 Mb - fullduplex.

� Devices on the PC port should not be allowedto run at 100 Mb because the uplink port to theaccess layer switch will only be 10 Mb.

Quality of Service (QoS)

The following types of QoS tools are needed fromend to end on the network to manage traffic andensure voice quality:

� Traffic classification—Classification involvesthe marking of packets with a specific prioritydenoting a requirement for class of service (CoS)from the network. The point at which these pack-et markings are trusted or not trusted is consid-ered the trust boundary. Trust is typically extend-ed to voice devices (phones) and not to datadevices (PCs). In general, the recommendationis to classify or mark traffic as close to the edgeof the network as possible. Traffic classification isan entrance criterion for access into the variousqueuing schemes used within the campusswitches and WAN interfaces. The IP phonemarks its voice control signaling and voice RTPstreams at the source, and it adheres torequirements for voice, video, data, and signal-ing and control traffic. (See Figure 13.)


� Queuing or Scheduling—Interface queuing orscheduling involves assigning packets to oneof several queues based on classification forexpedited treatment throughout the network.After packets have been marked with theappropriate tag at Layer 2 (CoS) and Layer 3(DSCP or PHB), it is important to configure thenetwork to schedule or queue traffic based onthis classification, so as to provide each classof traffic with the service it needs from the net-work. By enabling QoS on campus switches,you can configure all voice traffic to use sep-arate queues, thus virtually eliminating thepossibility of dropped voice packets when an

interface buffer fills instantaneously. Althoughnetwork management tools may show that thecampus network is not congested, QoS toolsare still required to guarantee voice quality.Network management tools show only theaverage congestion over a sample time span.While useful, this average does not show thecongestion peaks on a campus interface. Forconverged networks, switches that have atleast two output queues on each port and theability to send packets to these queues basedon QoS Layer 2 and/or Layer 3 classificationare recommended. (See Figure 14.)

Figure 13. Conditioning Packets to Ensure Quality of Service



� Bandwidth Provisioning—Provisioning involvesaccurately calculating the required bandwidthfor all applications plus overhead. In the cam-pus LAN, bandwidth provisioning recommen-dations can be summarized by the motto, overprovision and under subscribe. This mottoimplies careful planning of the LAN infrastruc-ture so that the available bandwidth is alwaysconsiderably higher than the load and there isno steady-state congestion over the LAN links.

If QoS is not deployed, packet drops and excessivedelay and jitter can occur, leading to impairments ofthe telephony services. When media packets are sub-jected to drops, delay, and jitter, the user-perceivableeffects include clicking sounds, harsh-sounding voice,extended periods of silence, and echo.

When signaling packets are subjected to the sameconditions, user-perceivable impairments includeunresponsiveness to user input (such as delay to dialtone), continued ringing upon answer, and doubledialing of digits due to the user's belief that the firstattempt was not effective (thus requiring hang-upand redial).

Until recently, quality of service was not an issue inthe enterprise campus due to the asynchronousnature of data traffic and the ability of networkdevices to tolerate buffer overflow and packet loss.However, with new applications such as voice andvideo which are sensitive to packet loss and delay,buffers—not bandwidth are the key QoS issues inthe enterprise campus.

Auto-Management Functions

In many third and fourth generation converged net-work switches, the automation of QoS capabilities isprovided by integrated switch software, in hardwareand in network management tools. This simplifiesthe provisioning and on-going support for QoS andsecurity configuration and management tasks.Additionally, automation of these functions improvesconsistency, and performance of the converged net-work due to the elimination of manual processes.

Figure 14. Segregating Packets by Delay Characteristics



UPS and Power Backup

In general, two to four hours of UPS backup isdesired for most locations. A secondary level ofbackup can be provided for major network operatingcenter locations by providing backup generators forthese locations in addition to UPS power. This is rec-ommended for larger sites and centralized sites thatpower IP Communications servers and provide cen-tralized gateway services to the PSTN or serviceprovider networks with integrated switches or routermodules, or use stand-alone gateway devices.

Multi-Layered, End-to-End SecurityTechnologies

A systematic approach to securing a converged net-work is the best defense against attacks on the net-work infrastructure. Organizations must develop andemploy comprehensive tools to rapidly identify, pre-vent, and adapt to security threats.

The dramatic spread of worms such as Slammer andBlaster highlights the need for multiple levels ofdefense, where many security functions interoperateto mitigate threats throughout the network.

A security policy defines who can do what, where,and when, while a security posture assessment canidentify vulnerabilities and suggest fixes.

Security solutions and tools can be organized intothe following three categories:

� Threat defense—watches for improper behav-ior in the network; examples include firewallsand network- and host-based intrusion detec-tion/prevention systems (IDS/IPS).

� Trust and identity management—permits ordenies services to devices and users based onpolicies; an example is a Remote Access Dial-In User Services (RADIUS) access controlserver.

� Secure connectivity—provides confidentialityacross public links such as the Internet; forexample, a virtual private network (VPN) withencryption.

A comprehensive security strategy involvesapproaching security solutions in "layers" so thatexposure in any one layer or set of technologies iseffectively mitigated by security protections and toolsin other layers.

A comprehensive security solution requires manage-ment of network devices as well as security devicesand solutions that span both. Generally, to provide acomprehensive solution, the following components arefound in the converged IP Communications network:

� Host Intrusion Detection / Prevention—HostIntrusion Detection/Prevention software oneach server can mitigate virus and wormattacks, as well as ease the patching andmaintenance burden.

� Firewalls—Placing integrated firewall modulesbetween zones efficiently enhances threatdefense for the different application and serverenvironments against directed and indiscrimi-nate security attacks.

� Network Intrusion Detection, NetworkAdmission Control, Virus Protection—Network access devices enforce admissioncontrol policy by demanding host security "cre-dentials" from endpoints requesting accessand relaying information to the policy servers;access devices then permit, deny, quarantine,or restrict access according to policy. Policyservers evaluate endpoint security informationand determine the appropriate access policy toapply.

� Identity Based Admission Control w/ DigitalCertificates—Enforce strict password ruleswith frequent password rotation. While themost secure options are one-time password ordigital certificate systems, not all enterprisescan afford them. Certificates, encryption andauthentication tools can also be used for IPApplications software on the converged net-work to ensure that all endpoints, servers arerunning authenticated software.

� Access Control Lists for Protecting Layer2/3 —For Layer 2 networks use 802.1X port-based authentication. For Application servers,close unused ports on all devices and expireuser passwords after a specified period;enforce strong password rules. In wireless


deployments, go beyond WEP when securingthe wireless LAN, and regularly look for rogueaccess points. Conduct periodic securityaudits of the network, preferably by qualified,independent internal security specialists or areputable third party. Configure access controllists (ACLs) to conform to security policies.

� Network Segmentation—Compartmentalizethe network into security "zones" and definepolicies for each one, including access rulesand rules for how zones interact. Use ofVLANs enables zones to be created for the dif-ferent tiers (for example, Web, application, anddatabase) within multi-tier applications andbetween different applications.

� Remote Access—Where users requireremote access to data center applications, useIP Security (IPSec) VPNs or Secure SocketsLayer (SSL) VPNs for partners. Also use VPNsfor interconnecting remote data centers forbackup and replication.

� Other Security Network Technologies—Using quality of service (QoS) features, you canminimize the impact of distributed denial of serv-ice (DDoS) attacks. This is done by configuringnetwork-based application recognition (NBAR)to filter worms and unpermitted HTML traffic andby using Layer 2 security features such asDynamic ARP Inspection (DIA) and DynamicHost Control Protocol (DHCP) snooping to pre-vent spoofing. You should also disable routerservices that hackers commonly exploit such asFinger, BOOTP, and Proxy-ARP.

Implementation Considerations—Centralized, Distributed, or Autonomous?

One question that must be addressed is the extent ofdeployment of VoIP. Is this a centralized, distributed,or autonomous deployment, or is it a combination? Ifagencies manage their own LANs, it could well bethat a VoIP system could be autonomous anddeployed agency by agency. If this is the case, itwould be in the best interests of all if establishedstandards were followed so that the systems arecompatible across the enterprise.

A distributed deployment would be the best option toprovide the toll savings that is so often given as areason to deploy VoIP. In this instance, numerousdistant locations are networked together, and canachieve toll bypass when calling between any of thelocal calling areas on the network. A good applicationof this would be networking all of the offices for a sin-gle agency throughout the state.

A centralized deployment would aggregate the great-est number of individuals on the platform, hubbingthe traffic to specific locations. This would be advan-tageous in passing VoIP traffic to a provider, whichwould take advantage of the bulk minutes used toget any decrease in toll rates.

The latter two options may require a phased approach.The larger the location, the longer it will take due tofunding issues or deployment schedules. This shouldcertainly be considered when making decisions; theoption with the least impact to the end user shouldhave an edge in that factor of the analysis.

Mix of Broadband, WAN, MAN, LAN, and PSTN

In evaluating the support for convergence network-ing options, the various WAN, MAN, LAN, PSTN andWireless networking options should be considered.Typically, support for both digital and analog PSTNvoice interfaces is needed for IP to PTSN networkinggateways requiring data rates up to or exceedingT1/E1 speeds. The range, type and flexibility ofVoice and Data Interface cards, modules within ded-icated or stand-alone gateways should be evaluated.In additional to providing robust support for PSTNnetworking, routers, gateways and switches shouldbe evaluated in terms of how many, and what typesof wide area network, broadband network, and LocalArea Network Interfaces they support. For WAN net-working, are ATM, Frame Relay, IP, and MPLS sup-ported? For the MAN (Metropolitan AreaNetworking), can metro dark fiber be used? Do theswitches or routers support termination of fiber forGigE or metro-Ethernet transport equivalents?

With dark fiber and MPLS services frequently avail-able within existing government owned or leasedfacilities, and often available from local and national


service providers, the incremental cost of supportingmany sites with common high speed networkinginfrastructure can be significantly reduced. Someapproaches that governments are successfully usinginclude having their own dark fiber, with optical con-nections now readily available in next generationintelligent networking equipment. Another approachis to use an existing spare lambda (light wavelength)on an existing fiber plant from a service provider.Many governments are also adopting a cost effectiveand flexible MPLS service that connects all of theirsites together with quality of service guarantees. Allof these approaches can dramatically lower the costof converged networking infrastructure supportcosts, while enabling improved quality and increasedflexibility to deploy progressive productivity gainsfrom new applications over time.

Within the LAN, consider if the network is currentlyprepared to handle voice traffic. The rule of thumb forQoS capability is a 100 MB Ethernet backbone, butideally, GigE uplinks and priority queuing capabilitieswithin switching infrastructure should be present toproperly address latency, jitter, and delay for largermulti-site and campus networks.

The cable plant will need to be professionallyinstalled and certified for Category 5E or greaterwiring. This will provide a physical layer that meetsthe minimum VoIP requirement. If utilizing GigE, alllegacy Category 5 wiring will need to be tested andcertified to support GigE. A service provider thatsupports Multi-Protocol Label Switching (MPLS)managed services will need to be considered if aQoS protocol (such as TDM/ATM) is not available.

Flexibility, Scalability, Resiliency, andAvailability

Another aspect of VoIP service will be the how thenetwork is designed and placement of servers inorder to maintain a high degree of reliability. DiversePSTN connections, meshed network access, diversephysical paths, backup power, database mirroring,are a few of the issues that must be addressed priorto any implementation.

Security

As touched upon in the Value Proposition section,having multiple agencies with partial ownership ofthe underlying routers and network provides com-plexity that will impact deployment. Security is onelarge area, as all of the agencies would need to worktogether. Each firewall encountered can cause varia-tions in the output, some to the point of a failed call.Each installation should include a full analysis of theexisting security that is in place, how that is provided,and how any VoIP equipment or traffic will react tothat situation. Similarly, the agencies involved wouldneed to determine policies and procedures to dealwith troubleshooting, how, when, and who performsupgrades on the routers, so that the network as awhole can be maintained with the utmost of integrity.These steps would have to be done even if onedepartment maintained ownership of the network, butin that event, the determination would be much easi-er as many of those processes would already exist.

Training, Support and Maintenance

Because converged communications applicationstightly rely on close integration with the underlyingintelligence in the network, it is a good idea to havea business continuity plan in place. Applicationdevelopers and IT staff responsible for infrastructureneed to be sensitive to the ripple effect that even asmall change may have. Cross discipline training isalways a good idea. Once fully deployed, your con-verged network will need to have 24x7x365 globalsupport to avoid costly down time.

E911 Considerations

An E911 service has to provide automatic numberand automatic location information (ANI and ALI) toa 911 public safety answering point (PSAP) when anemergency call is made. Most traditional PBX's areonly able to provide this support with third-partyassistance and a lot of administration. Local num-bers must be updated regularly as new codes areassigned to phone companies, wireless carriers, etc.Some states have laws mandating private switch


enhanced E911. The National Emergency NumberAssociation (NENA) has a current list of such laws<http://www.nena9-1-1.org/9-1-1TechStandards/state.htm>.

To appreciate the unique issues of E911 support inIP telephony, consider how emergency calls are han-dled with a traditional PBX. When an emergency callis made, information is typically sent to a securitystaff relating the caller's physical location on thecampus with their extension number. When an emer-gency team (e.g., police or fire department) arrives,an employee can meet the team and direct them tothe emergency.

The issue to be solved here is that an IP phone canbe moved without any centralized administrativeintervention. A database has to be maintained tomap the IP phone's unique Layer 2 addresses to aphysical location now being served by a port on aswitch. This is not the case with a traditional PBX,which just maps a port to a phone.

IP telephony offers two basic approaches to handlingemergency calls: on-net to campus security or off-net to the carrier Point of Presence (POP). With on-net campus security, usually an individual in thecompany assists the 911 respondent; with off-netapproach, the number and location of the individualin distress is made available to the PSAP.

Dial Plans

The dial plan architecture includes dial plan groups,calling restrictions, and on-net route patterns. Thisincludes defining which gateway to use when some-one makes a long distance call, or which PSTNtrunks to use for domestic versus international calls.For a "least cost routing" example, consider the fol-lowing: If someone in Dallas wishes to call off-net-work to a person in San Antonio, the call can be rout-ed over the enterprise network and get handed off tothe public phone network via a gateway in SanAntonio, thereby being charged only for a local callinstead of a long distance call from Dallas to SanAntonio.

VoIP Vendors

Major telephony equipment vendors now have stablesolutions to complement their traditional TDM voiceswitching gear. Network infrastructure vendors haveoptimized their products specifically for convergedapplications and are working closely with applicationvendors to fully exploit the underlying intelligence inthe network. Enterprises now have a choice ofproven solutions and no longer have to be lockedinto a single vendor in order to enjoy an end-to-endsolution. According to August 2004 GartnerResearch, the following vendors have established acredible presence in the North American IPTelephony market:

Leaders (Product portfolios and market strengthaffecting overall market trends)

Avayahttp://www1.avaya.com/SEO/IPTelephonyA/

Cisco Systemshttp://www.cisco.com/en/US/products/sw/voicesw/index.html

NEChttp://www.neaxnet.com/

Nortel Networkshttp://www.nortelnetworks.com/products/voip/pureip.html

Siemenshttp://www.siemens.com/index.jsp

Niche Players (Strong product offerings for specificmarket segments)

3COMhttp://www.3com.com/products

Inter-Telhttp://www.inter-tel.com

ShoreTelhttp://www.shoretel.com/STCorp/

http://www1.avaya.com/SEO/IPTelephonyA/

http://www.neaxnet.com/

http://www.siemens.com/index.jsp

http://www.3com.com/products

http://www.inter-tel.com

http://www.shoretel.com/STCorp/

http://www.nena9-1-1.org/9-1-1TechStandards/state.htm

http://www.cisco.com/en/US/products/sw/voicesw/index.html

http://www.nortelnetworks.com/products/voip/pureip.html


Toshibahttp://www.toshiba.com/taistsd/pages/prd_cti_main.html

Vertical Networkshttp://www.verticalnetworks.com/

Visionaries (Innovative companies with the potentialto influence the market)

Alcatel Networkshttp://www.alcatel.com/

Mitel Networkshttp://www.mitel.com/

http://www.verticalnetworks.com/

http://www.alcatel.com/

http://www.mitel.com/

http://www.toshiba.com/taistsd/pages/prd_cti_main.html


The Federal Communications Commission (FCC)under former Chairman Michael Powell took thestand that the regulation of VoIP would not be sub-ject to traditional state public utility regulation. TheFCC has set up a working group to identify policyissues addressing the migration of communicationsservices to Internet-based platforms. The most hotlycontested debate is over whether VoIP technologyshould be regulated in an approach similar to tradi-tional telephone services, which leads to taxationissues regarding calls flowing between states. TheFCC has taken the position that moving more com-munications to IP is in the public interest. ChairmanPowell stated publicly, ". . . The policy environmentmust begin with the recognition that the Internet isinherently a global network that does not acknowl-edge narrow, artificial boundaries. I (absolutely)believe in maintaining an Internet free from govern-ment regulation and firmly support the idea that VoIPshould evolve in a regulation-free zone."

In fact, in November 2004, the FCC effectively pre-empted the states from having jurisdiction onInternet telephony. The commission voted 4-1 toexempt Vonage Holdings Corp.'s DigitalVoice VoIPphone service from Minnesota telephone taxes andcertification standards, including 911 emergency callcapability. In taking Vonage's side in its dispute withMinnesota, the FCC set a standard it says is essen-tial to free the VoIP industry from state laws that canhinder growth and prosperity. The decision adds tothe regulatory certainty the Commission began build-ing with orders adopted earlier this year regardingVoIP by making clear that this Commission, not thestate commissions, has the responsibility and obliga-tion to decide whether certain regulations apply toIP-enabled services. The Commission has the powerto preempt state regulations that conflict with, orimpede, federal authority over interstate communica-tions.

VoIP regulatory environment


The "connected" office worker in the near future willbe able to remain connected regardless of wherethey are located. Wi-Fi / Wi-Max enabled portabledevices and VoIP enabled applications will extendthe enterprise to them anywhere, any time. In mov-ing to a converged voice, data, and video network,

organizations will need to "future-proof" their infra-structure in order to support multi-media interactionswith constituents and support the connected tele-worker. (See Figure 15.)

the vision of VoIP

Figure 15. Technology Support for the "Connected" Teleworker

Source: Tom Shepherd, ITE, IA


Section I—General

1. What is VoIP? Is it the same as IP telephony oris it different?It is helpful to think about IP Telephony separate-ly from IP transport for a number of financial andoperational reasons. VoIP uses an IP transportlayer between voice switches to complete phonecalls instead of the traditional dedicated circuitry.VoIP is being used today by many of the Inter-exchange Carriers to transport calls throughoutthe nation, with the traditional PSTN being usedto originate and terminate the calls. This makesthe change to VoIP transparent to the end user aslong as proper bandwidth and QoS are allocatedto the voice calls. IP telephony is different in thatit extends the IP network all the way to the desk-top, bypassing the PSTN completely. (Also, seepages 6-9.)

2. Is VoIP the right technology?In the traditional voice deployment, dedicatedfacilities are required. In a VoIP deployment,where IP is the transport portion only, this is calleda hybrid application. The transport is IP, whichcan save money on toll charges between intra- orinter-LATA locations, but the desktop handsetswould be unaffected. In a pure IP deployment, orIP telephony deployment, there is no conversionto TDM at any point in the network. The decisionas to which technology is the right one for any sit-uation will depend on the existing infrastructure.In some instances, the existing cable plant is suf-ficient and replacing that with a pure IP solutionwould be too costly, since that may includeupgrading existing routers to be QoS capable, aswell as replacing existing handsets. If these itemsare nearing end of life anyway, it may be costeffective to examine an IP telephony deployment.

3. Does VoIP support transformation of the busi-ness of serving the public?Using the definitions provided in no.1 above, VoIPcould improve serving the public as it could very

well lower toll costs. The Applications associatedwith IP Telephony could certainly improve servic-es to the public by increasing the accessibility ofpeople at all levels of government, improvingresponsiveness, and facilitating collaborationbetween the public and government employeesand improving the efficiency of public employees.

4. How does all this VoIP activity relate to myrelationship with the various Telco's in mystate?Telco's will see inter- and intra-state accesscharges decline as VoIP is implemented. Some ofthe larger telcos have opted to provide VoIP ontheir own network to retain the customer base.While a considerable amount of money can besaved by implementing a VoIP solution, this maynot prove to be a financially sound model forevery location, and there will still be a number ofcalls that will go to the PSTN or to an alternateVoIP provider for termination. Balancing the sav-ings achievable with the on-going relationshipswill be a challenge if the Telco's see their revenuestreams decreasing. The adjustment will be thatmore bandwidth is needed to do VoIP, so theoverall loss of voice origination/termination maybe limited somewhat by additional circuit or band-width requirements. The value proposition of VoIPfor individual organizations is in the differenttrunking and transport options. (See section onMajor IP Communications Solutions, page 9.)

5. Are we better off waiting for the LECs to pro-vide VoIP or should we build our own "phonesystem?" How do we make this decision?Looking at this from the two perspectives of VoIPand IP telephony might help clarify this. Theanswer depends on the level of expertise avail-able. If you currently manage your own phonesystem, and have IP knowledge within the organ-ization, it probably makes sense to maintain an in-house system, particularly with a VoIP deploy-ment—meaning transport only. IP telephony mayrequire a more significant overhaul of the system,

state CIO VoIP/IP telephony questions


and a cost-benefit analysis will have to be done todetermine the best path forward for each organi-zation. There are different drivers for the imple-mentation of VoIP Transport and IP Telephony.You will need to assess the value proposition ofownership vs. leasing or renting from the carrier.

6. What is the regulatory climate surroundingVoIP? How may that eventually impact myoperation?The regulatory climate is beginning to clarify itself.One of the largest areas of disagreement is thearea of access fees, and it is anticipated arevamping of the current system will be requiredin the near future to ensure universal coverage.The E911, Communications Assistance for LawEnforcement Act (CALEA), and disability accessare areas currently being addressed by the indus-try, which are critical for state applications.

7. What is the future of VoIP?Call centers are a great use of VoIP; the technol-ogy is here to stay. More and more residentialcustomers are moving to VoIP as a primarymeans of communication, though there is still lessthan one percent of homes that have gone toVoIP. The business community has embracedusing VoIP more completely, as there are moredollars to be saved by connecting their largestcenters together without having toll charges orhaving to maintain dual data and voice facilities.According to TEQConsult Group in Hackensack,N.J., new VoIP lines are on track to hit 40 percentof all U.S. lines installed in 2004 and should passthe 50 percent mark in 2005.


Section II—Reliability/Quality of Service/Security

1. What are the reliability expectations of gov-ernment users?Users have more communications options today,so expectations for any one technology aredependent upon the availability of other options.However, the expectation is that departments withpublic contact should maintain the highest level oftelephone availability, where departments with con-tacts mainly within the system would have e-mailas a back-up means of communication. Obviously,if the LAN and voice networks are combined, anissue in one may very well indicate an issue in theother. Generally, VoIP will be expected to have thereliability people are historically used to.

2. Can we create a solution that is reliableenough to approximate the current phonesystem?Yes, a solution can be implemented that is veryreliable. These solutions are vendor dependent,and as with any application, the analysis of reli-ability versus implementation and maintenancecosts will have to be examined to ensure thebest solution is selected. These are all part ofthe QoS equation and will need to beaddressed. Generally speaking, the higher thereliability requirements, the higher the cost will

be in supporting the VoIP service.

3. Can you give me a checklist of what I need todo to facilitate a good QoS?See VoIP Implementation and Planning Section,pages 24-28.

4. What QoS protocols and policies are availablein the IP network and how will we ensure QoSand traffic engineering?The specific QoS protocols are dependent uponthe vendor or service provider you choose.

PSTN QoS is handled by the Message TransferParts (MTP) 2 and 3 in the SS7 Protocol Stack.MTP Level 2 ensures accurate end-to-end trans-mission of a message across a signaling link.Level 2 implements flow control, messagesequence validation, and error checking. Whenan error occurs on a signaling link, the message(or set of messages) is retransmitted. MTP Level2 is equivalent to the OSI Data Link Layer.

MTP Level 3 provides message routing betweensignaling points in the SS7 network. MTP Level 3re-routes traffic away from failed links and signal-ing points and controls traffic when congestionoccurs. MTP Level 3 is equivalent to the OSINetwork Layer. (See Figure 16.)

Figure 16. OSI Layers—Signaling System 7 Protocol Stack

Source: Intel Corporation


5. How secure are IP service offerings?The level of security depends a great deal on thenetwork design and vendor equipment selected. Ifthe network is designed with limited connectivityto the public internet, those connections can bemonitored to protect or minimize against a DoS(Denial of Service) attack or SPIT (SPam overInternet Telephony). Links to a couple of recentarticles on this topic can be found at:

"Watchguard Brings Firebox Model to Small Nets"http://www1.commsworld.com.au/NASApp/cs/ContentServer?pagename=commsworld/home&var_el=art&art_id=1084814734726&var_sect=NEWS&from=home

"Spam, DoS Headed VoIP's Way"http://www.enterpriseitplanet.com/security/news/article.php/3398951

6. Since VoIP necessitates "always on" Internetconnectivity, what security implications arethere?Any device with an IP address will have securityimplications. To mitigate that impact, VLANs,internal IP numbering, etc, should be considered.Managed networks would be the most secure touse instead of using the public Internet.

http://www1.commsworld.com.au/NASApp/cs/ContentServer?pagename=commsworld/home&var_el=art&art_id=1084814734726&var_sect=NEWS&from=home

http://www.enterpriseitplanet.com/security/news/article.php/3398951


Section III—Cost Benefits/Funding

1. What are the real (visible and hidden) costsassociated with VoIP?VoIP transport will require properly trained sup-port staff and new routers, switches, power,increased bandwidth, and new servers. VoIP canbe implemented into the transport layer of the net-work and not affect the end devices. IP Telephonywould require the wholesale change out of hand-sets and switches as well as the addition of prop-erly trained support staff. IP Telephony can bedeployed slowly to the desktop, which wouldspread out the costs of deployment. Some userswould have IP handsets, and some would havedigital or analog handsets. The assumption is thatthe digital sets in use would be compatible withthe IP PBX.

2. What are the documented cost benefits ofmoving to VoIP and is there a true ROI modelI can utilize to determine when and how tomove to VoIP?

VoIP Savings for Organizations� Eliminate or reduce PSTN toll charges.� Reducing of eliminating service and sup-

port contracts on existing PBX hardware.� Eliminate the requirements for Centrex

services and charges.� Collapsing voice and data infrastructures,

support, and management resources intoone that represents savings in staff, main-tenance, upgrades and reduced costsassociated with moves, adds and changes.

� Reduce the on-going costs for the supportand maintenance of separate voice mes-saging systems.

� Provide productivity benefits for remote andtraveling workers by extending the enterpriseto them (e.g. providing them with the sameintegrated capabilities as office workers).

� Reduce user training and improve thelearning curve on phone and messagingsystems.

� Cost-effectively implement unified messag-ing. (Unified messaging is the integration ofseveral different communications media,such that users will be able to retrieve and

send voice, fax, and e-mail messages froma single interface. Unified messaging tech-nology provides the power to reach peoplealmost anywhere, at any time and the flexi-bility to allow people to control when theycan be reached and enable them to inter-face with messages how and when theywant. Subscribers reduce the number ofplaces they must check for incoming voice,fax, and e-mail messages).

� Improved security.� Reduced systems downtime and improve

performance.

Benefits for Call Centers� Enable the implementation of "Virtual" call

centers, allowing more flexibility in the cen-ter's configuration. This can facilitate callcenter consolidation efforts and provideenterprise capabilities to telecommutingcall center workers.

� Improve customer support services andreduce abandoned calls and call times.

� Improve customer satisfaction and reducecustomer turnover via improved call centerservices.

Cost Considerations� VoIP telecommunication hardware and soft-

ware.� IP phone sets or soft phones.� Network upgrades to ensure quality of serv-

ice and performance.� Implementation labor and professional

services.� On-going support and administration labor.� Support and maintenance contracts.� Increased support calls and potential user

downtime losses on initial deployment.� IT training.� User training.� Write-off, write-down and disposal costs for

existing telecommunication assets.

Potential VoIP Project Risks� Quality of service and network perform-

ance.� User training and adoption.� Administration and support skill levels and


resources.� Proprietary vs. open systems interoperabil-

ity.� Potential regulatory issues affecting the

costs associated with VoIP and IPTelephony.

In addition to direct benefits from VoIP, it is impor-tant to consider the costs associated with the lim-itations in the current PSTN. The inability to sup-port certain features (or do so cost effectively)reduce the business value of the PSTN overnewer, more robust technologies. For example:

� Growth in distributed staffing by manyorganizations require an adaptable systemfor call routing and toll avoidance. A tradi-tional PBX cannot do this (or may do so ina very limited manner). VoIP can deliver.

� Automatic reconfiguration during staffmoves. If you pick up an IP telephone andmove it into another office, the phone num-ber moves with the phone. The costs ofstaff moves for the legacy phone systemcan run up to $100 per person with a PBX,depending on the number and complexityof the moves.

Each traditional phone call uses a 64 Kbit/secondcircuit for the full duration of the call. During aVoIP call, the periods with sound take up thatsame bandwidth but periods of silence or a con-stant tone (assuming data compression) wouldtake much less. Because of this, VoIP can carrymore calls in the same bandwidth as a circuitbased system.

Quality of Service (QoS) is required to ensure thatyour calls are not adversely affected by youravailable network bandwidth. If jitter (e.g. varia-tions in the delay in the phone call) becomesexcessive, people are going to be annoyed withthe telephone system. If you have a dedicatedVoIP network and your load is always less thanyour network capacity, you will never need QoS.You need QoS when you have to prioritize (orration) the capacity to the benefit of some proto-cols and to the detriment of others. In otherwords, by turning on QoS capabilities in your net-work equipment, you prioritize the Voice mes-

sages to the detriment of Data messages. Thedata users won't notice they get delayed (unlessyour network is extremely inadequate) and thevoice users will be satisfied with the service.

3. Will anticipated cost savings be eaten up bytrying to ensure greater redundancy and relia-bility on data lines? Once you implement VoIP, you can reduce costssince you are only maintaining one networkinstead of two. If your data network is not alreadyredundant and reliable, the QoS requirements,even though they may prove to be costly, willeventually result in better service for agencies ata lower cost. It depends upon your individual situ-ation.

4. How will the transition to VoIP impact thenumber and cost of Centrex lines?Most of the LECs have tariff pricing based uponannual commitments of lines. Partial implementa-tion of VoIP may leave remaining lines with high-er costs. You will have to do the analysis.

5. There is a significant installed base of expen-sive traditional voice equipment that has notreached end-of-life. How do we implementVoIP when there are limited funds for replace-ment? Use the projected operational savings from a con-verged network to assist you in mapping themigration path to IP telephony.

6. Are there sufficient funds to build the IP net-work to a required level of availability?It depends upon the strength of your data net-work. What is the current reliability and availabili-ty of your current IP network and does it meetyour requirements today? Remember, you arecurrently maintaining 2 networks. What are theeconomics when you transition the telephonycosts to the IP network? In the short term, therewill probably be additional costs—in the longterm, you should see cost savings from a con-verged network. You should explore variousfinancing options that spread the costs out over areasonable period.


Section IV —Implementation/Management

1. I have existing PBXs and voice switchingequipment. How can I phase in VoIP and lever-age my existing investments?VoIP, at the transport layer only, can be imple-mented fairly easily while still maintaining theexisting PBXs, handsets, etc. This merely allowsthe toll savings and the combination of data andvoice traffic onto one or multiple circuits whichshould decrease costs compared to maintainingseparate trunking for each. IP telephony throughIP to the desktop might be a natural progressionas the existing equipment is ready for replace-ment. Remember, many PBXs can be IP enabled.

2. Do I have to buy new telephones?A VoIP implementation (transport layer) would notaffect handsets at all. If you wish to implement IPtelephony, then new telephones would berequired.

3. Can our existing systems (PBXs, Centrex,etc.) and network co-exist with IP switching?Will network be scalable and adaptable to ourpresent and future needs?It depends on the engineering and capacity ofyour existing network. Routers must be QoScapable and of adequate capacity. The RFI orRFP process can help determine the best solutionfor the specific situation.

4. Are there any future improvements that wouldcause me to hesitate with my implementationtoday?The standards today for IP telephony are incom-plete and still being determined in the industry, somost vendor solutions will be proprietary. Thisdoes not impact the transport layer, however, soVoIP can be deployed on the transport level toreap the benefits. The drivers for IP telephony aredependent upon your costs for implementationand the urgency of implementing IP Telephony-based applications.

5. Will the VoIP strategy and infrastructure allowthe VoIP to be rolled out on an opportunisticbasis?Simply put, yes. Each office may not have the

level of voice traffic to make a VoIP investmentworthwhile. Financially, it makes more sense for aremote office environment at this time and muchless sense for a campus environment. A migrationplan spanning any length of time may cause dif-ferences to the end user that cannot be avoideddepending upon the current technology and thesolution being implemented. It is important tounderstand these implications before starting theproject so the users can be adequately informedof any changes.

6. How do I manage the fact that ownership ofthe various routers, switches and compo-nents of my network are distributed amongthe agencies in my state?If you are trying to go to IP telephony, it MUST bea standards-based implementation. All agenciesinvolved must comply with those standards. Thisis a converged network and must be effectivelymanaged for quality, reliability and security.Otherwise, a VoIP implementation is still anoption to save on the circuit or toll costs, while notimpacting the individual LANs/WANs of the indi-vidual agencies. It may be desirable to establishcommon resource or funding pools and stan-dards-based procurement requirements for VoIPimplementations.

7. Does VoIP necessitate centralized manage-ment of voice infrastructures and strategies?Consistent voice network architecture?Converged voice and data networks in theWANs/MANs?VoIP doesn't require centralized management. Aslong as the routers can pass the traffic, the trans-port layer isn't a difficult conversion. However, interms of IP telephony, there would have to besome attention to being consistent across the net-work. A converged network isn't necessarilyrequired, but to maintain two separate networks iscostly in terms of duplicate routers, cabling, andall environmentals associated with that extraequipment.

8. Can a VoIP solution be effective if we don'toperate the whole network, including theLANs?As in question no. 6 above, a VoIP solution can


be implemented, but an IP telephony solutionwould be complex. To do IP telephony, all LANswould have to be managed identically, any soft-ware upgrades would have to be coordinated,and trouble-shooting rules would have to be inplace to be able to adequately address anyissues. Without consistent management, strate-gies, and service level agreements (SLAs) of con-verged network stakeholders, VoIP will have ahard time approaching the five-nines reliability ofthe current circuit-switched phone systems.

9. What organizational changes must be made toeffectively implement IP telephony using aconverged network?In order to be responsive to the requirements ofIP based phone services, a role and responsematrix must be established for LAN technicians.You should also provide additional training anddesignate technicians with a primary responsibili-ty for IP telephony.


Section V—Emergency Services/DisasterPlanning

1. What are the implications of VoIP in the areaof enhanced 911 (E911) coverage?Some VoIP systems (no firm estimates on thenumber) will be able to offer E911 services by thethird quarter of 2005. E911 service refers to theability to route calls directly to an emergency dis-patcher with the caller's location and phone num-ber appearing automatically.

VoIP 911 calls are currently routed through publicsafety access points (PSAPs)—facilities where anoperator can alert emergency response agencies.These PSAPs don't have Data ManagementSystem/Automatic Location Identification(DMS/ALI) systems, which allow operators toimmediately identify the caller's location. SinceVoIP carriers aren't regulated, they don't haveaccess to E911 selective routing. So, for the fore-seeable future, each provider must come up witha solution and pass the cost on to consumers.

Some VoIP providers and cable operators offerE911 as a subscription service. One VoIP providerwith 1,700 subscribers charges a $9.95 setup feeplus $3 a month. Even with this E911 service, theVoIP provider urges consumers to seek emer-gency services elsewhere. User agreements fromVoIP providers 8x8 Inc., Verizon CommunicationsInc., and others advise consumers to "maintain analternative means of accessing traditional 911services." VoIP users can't dial 911 during apower, Internet, or other network outage.

A selling point of VoIP services is that it's portable.Once you move to a new location and reconnect,any location information registered with your VoIPservice provider is invalid and 911 won't work cor-rectly. You have to register your new geographiclocation, which currently takes days to beprocessed.

VoIP service providers are working to develop asmarter E911 system that would identify a caller'slocation and route calls to the nearest PSAPregardless of the caller's pre-registered address.

This functionality will probably not be generallyavailable until 2006 or after.

2. What network disaster plans should be inplace?PSTN Reliability is typically associated with anability to get a dial tone, which is much differentthan actually being able to complete a call with anacceptable QoS. Plain old telephone service(POTS) subscribers in densely populated areaswith very old local wiring loops serving the apart-ments, houses and businesses can all recountstories of phone outages or degraded call qualityon rainy days. The same holds true for rural cus-tomers served by aging infrastructure. In contrastto their circuit-switched counterparts, packet-switched networks fundamentally enable fault tol-erance, adaptive routing, and disaster recovery. Itis quite possible—and can be quite cost-effective—to build IP-based voice systems that are morereliable than circuit-switched PBX platforms. Thekey is to start with the right foundation. Today'sVoIP solutions fall into three basic categories:

1. Systems evolved from traditional PBX plat-forms;

2. Systems evolved from traditional data-switch platforms; and

3. Systems designed from the ground up forVoIP.

All three of these architectures can be used todeliver VoIP systems with five-nines reliability, butthey involve different degrees of complexity andcost.

Legacy PBXs and key systems are hierarchicalvoice silos that operate independently at eachlocation in a multi-site company. They cannot backeach other up or be managed as a single voice net-work, and create a single point of failure at eachsite. IP networks are inherently distributed andresilient. VoIP architects starting with a blank slatecan exploit this fundamental strength to create aself-healing voice platform. A truly unified voicesystem can be distributed across multiple sites byusing a simple peer-to-peer architecture that hasno single point of failure. Your VoIP/IP Telephonyimplementation must take advantage of thesedesign features.


Additionally, there are product and service offer-ings from vendors, such as Cisco's SurvivableRemote Site Telephony (SRST) feature. TheCisco IP Communications Solution utilizes CiscoCallManager in combination with SRST in toenable organizations to extend high-availability IPtelephony to their small branch offices.

http://www.cisco.com/en/US/products/sw/voicesw/ps2169/products_data_sheet09186a00800888ac.html

3. Will IP equipment suppliers support us in a dis-aster?This is dependent upon your relationship andcontract with the provider(s).

http://www.cisco.com/en/US/products/sw/voicesw/ps2169/products_data_sheet09186a00800888ac.html


Section VI—Technical

1. I have a large number of devices on my net-work. At any given time, I have some isolatedpower outages. What can I do in this scenarioto avoid any voice outages? What aboutpower failures?

In regard to using VoIP to transport voice packets,the issues are the same as they are with your cur-rent network reliability. The complexity increasesdramatically when it gets to IP telephony.Redundant power availability should be built intoany solution if up-times are to rival the currentstandard 99.999 percent PSTN availability. Thiswill also impact the environmentals (e.g. HVAC) ofthe equipment location.

The primary reason for the switched phone net-work's superior reliability lies in the reliability andredundancy of network components, both in hard-ware and software. Phone network switches aredesigned for reliability. Because their hardwarecomponents represent only a small fraction oftheir price, and physical size is not a dominantconsideration, switch hardware engineers canafford to be conservative. But the real storyregarding hardware reliability is redundancy—justabout anything that could cause significant out-ages upon failure is backed up. Critical proces-sors typically are in "hot standby," meaning that ifone fails, a second one immediately assumes allfunctions without dropping a single call. Andpower systems are backed up with batteries andgenerators so that the phones keep workingindefinitely in the event of a widespread commer-cial power outage.

It has been reported that for every hour spentwriting switch software code, almost 200 hours isspent testing it. When it comes to the phone net-work, it's not good enough to find and fix softwarebugs after they cause an outage.

VoIP is architecturally sound and cost-effective,but the servers and routers that provide connec-tions to individual users currently are less reliablethan telephone switches in both hardware andsoftware design. Until that gap is reduced, VoIP

will not achieve the same levels of overall reliabil-ity as consumers now expect from the circuit-switched telephone network. This will take con-siderable attention to engineering your VoIP andIP telephony solution.

2. How do we ensure 99.999 percent uptime forvoice?For IP telephony, each vendor will have a solutionbased on the design of the network and the indi-vidual customer's needs. The important items tokeep in mind are uninterruptible power and secu-rity. Additionally, most vendors encourage a con-nection to the PSTN at each location to ensurecall completion. Good design practice will allowyou to achieve 99.999 percent availability.Reliable LAN and WAN infrastructures supportingpower protected clustered enterprise-classservers currently deliver five nines availability.Reliability can also be extended to remote sitesby deploying features such as Cisco's SurvivableRemote Site Telephony, ensuring telephony serv-ices remain functional even in the event of a WANfailure.

3. What are the interoperability issues aroundVoIP? What components do we need to con-cern ourselves with regarding interoperatingwith multiple vendor equipment?There are uniform industry standards at all levels,IP telephony interoperability can be provided bythe vendors themselves. Most do testing withcompetitor's products to determine where interop-erability is an issue and where it isn't. On the VoIPside, where a transport solution only requires therouters to pass IP traffic, standard procedureswould apply here.

4. How does the network design handle conges-tion?This really does depend on how the network isdesigned. Most vendors encourage maintainingconnectivity to the PSTN so that when calls areblocked on the IP side, they can use the PSTN asa backup route.

5. Are network devices compatible or upgrade-able to support VoIP?This really depends on the devices that are


currently deployed. Some devices will be—somewon't be. Some devices may already be VoIPenabled.

6. How are lost packets handled?Proper LAN, WAN, and Gateway design andenabling QoS on the voice trunks will be neededto address these issues up front. VoIP packetsare not retransmitted.

7. How will we handle loss of network synchro-nization?In a VoIP solution, the network synchronizationwould not change as the existing data routerswould take over this function. In terms of an IPtelephony deployment, the handsets will be timedoff of the switch. Each vendor should provideinformation on how the equipment reacts to lossof network synchronization and what is requiredto restore.

8. Can we accurately predict traffic volumes?This information should be available either in-house or through your current provider. The antic-ipated call volume, minutes of use, and number ofseats using any given trunk would be incorporat-ed into sizing that trunk appropriately.

9. How well do carriers understand IP switch-ing?Most of the Inter-exchange Carriers and majorIncumbent Local Exchange Carriers have beenusing IP switching on some level for severalyears. The smaller the carrier, the less likely theyare to have a deployed IP network, though thereare certainly exceptions.

10.What are the technical support considera-tions that we need to be aware of?For a VoIP solution, the issues will be the sameas that of regular IP traffic. You will want to ensureQoS is available on the routers.


Section VII—Applications

1. What applications will be supported for VoIPand can you give me specific case studies?See page 15 for a list of IP Telephony applica-tions. See the following page for case studies.


"Localized Mobility"—March 2005, GovernmentTechnology Magazine

http://www.govtech.net/magazine/channel_story.php?channel=19&id=93338

"Nortel Leads the Way in VoIP Applications ThatSupport Teleworkers"—December 2003, NetworkWorld Fusion

http://www.nwfusion.com/reviews/2003/1208rev.html

"IP Telephony Applications"—Nortel Networkshttp://builder.itpapers.com/abstract.aspx?scid=6&dtid=2&docid=81001

Web cast—"IP Voice from the Inside: The CNETCase Study"—Shoreline Communications

http://builder.itpapers.com/abstract.aspx?scid=6&dtid=2&docid=37375

Cisco Customer Video Case studies are located at:http://newsroom.cisco.com

Additional Cisco case studies can be found at the fol-lowing links:

http://www.cisco.com/en/US/strategy/government/all_local.htmlhttp://www.cisco.com/go/ipc

links to articles and case studies

http://newsroom.cisco.com

http://www.cisco.com/go/ipc

http://www.govtech.net/magazine/channel_story.php?channel=19&id=93338

http://www.nwfusion.com/reviews/2003/1208rev.html



http://www.cisco.com/en/US/strategy/government/all_local.html


802.3af

802.11 a/b/g

ACD

An IEEE standard for powering network devices via Ethernet cable. Alsoknown as "Power-over-Ethernet," it provides 48 volts over 4-wire or 8-wiretwisted pair. The 8-wire cable uses one twisted pair for the power, while the4-wire transmits the power over the same pair as the data, but uses differentfrequencies. Designed with IP phones and wireless access points in mind, itallows devices such as these to be placed in locations that have no electricaloutlets. Only the Ethernet cable needs to be connected to the device.

802.11 refers to a family of specifications developed by the IEEE for wirelessLAN technology. 802.11 specifies an over-the-air interface between a wire-less client and a base station or between two wireless clients. The IEEEaccepted the specification in 1997.

There are several specifications in the 802.11 family:

802.11 - applies to wireless LANs and provides 1 or 2 Mbps transmission inthe 2.4 GHz band using either frequency hopping spread spectrum (FHSS)or direct sequence spread spectrum (DSSS).

802.11a - an extension to 802.11 that applies to wireless LANs and providesup to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency divi-sion multiplexing encoding scheme rather than FHSS or DSSS.

802.11b (also referred to as 802.11 High Rate or Wi-Fi) - an extension to802.11 that applies to wireless LANS and provides 11 Mbps transmission(with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses onlyDSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allow-ing wireless functionality comparable to Ethernet.

802.11g - applies to wireless LANs and provides 20+ Mbps in the 2.4 GHzband.

See automatic call distributor.

VoIP/IP telephony glossary of terms

NUMBERS

A


ALI

ANI

ARP

Asynchronous TransferMode (ATM)

Auto Discovery

Automatic Call Distributor(ACD)

Automatic Location Identification provides for an address display of the sub-scriber calling 911. With ALI, the PSAP receives the ANI display and an ALIdisplay on a screen. The ALI display includes the subscriber's address,community, state, type of service and if a business, the name of the business.The PSAP will also get a display of the associated ESN information (police,fire and rescue).

Automatic Number Identification. A PSTN system that transmits the billingnumber of the calling party for accounting and billing purposes.

Address Resolution Protocol. Internet protocol used to map an IP address toa MAC address. Defined in RFC 826. Allows host computers and routers todetermine the data link layer address corresponding to the IP address in apacket routed through the LAN. Although the packet is addressed to an IPaddress, the LAN hardware responds only to data link layer addresses. Thehost or router with the destination IP address replies with its own data linklayer address in an ARP response, which the forwarding host or router willuse to construct a data link layer frame. The result is stored in cachememory so subsequent packets addressed to the same destination can berouted without an explicit ARP process.

A 53-byte cell switching technology well suited for carrying voice, data, andvideo traffic on the same infrastructure. It is inherently scalable in throughputand was designed to provide Quality of Service (QoS).

The process by which a network device automatically searches through arange of network addresses and discovers the known types of devices thatare present.

A specialized phone system that handles incoming calls or makes outgoingcalls. An ACD can recognize and answer an incoming call, look in its data-base for instructions on what to do with that call, play a recorded message forthe caller (based on instructions from the database), and send the caller to alive operator as soon as the operator is free or as soon as the caller haslistened to the recorded message.


B-ISDN

BOOTP

Broadband

Call Agents

CAS

Category 3/5/5e/6 Wiring

Broadband Integrated Services Digital Network. A network that employsswitching techniques independent of transmission speeds, and that allows anetwork to expand its capacity without major equipment overhauls. B-lSDNssupport gigabit speed circuits in the public network and high speed switchingof all traffic types in public and private networks. B-lSDNs also provide band-width-on-demand capabilities. Contrast with N-ISDN. See also BRI, ISDN,and PRI.

Bootstrap Protocol. A TCP/IP protocol that enables a network device todiscover certain startup information, such as its IP address.

High-speed voice, data, and video networked services that are digital, inter-active, and packet-based. The bandwidth is 384 Kbps or higher, and 384Kbps is widely accepted as the minimum bandwidth required to enablefull-frame-rate digital video.

Intelligent entity in an IP telephony network that handles call control in anMGCP model voice over IP network. Also known as a Media GatewayController (MGC).

1. Centralized Attendant Service. One group of switchboard operatorsanswers all incoming calls for several telephone systems located throughoutone city or region.2. Channel Associated Signaling. In-band signaling used to provide emer-gency signaling information along with a wireless 911 call to the Public SafetyAnswering Point (PSAP).

The type of twisted pair copper cabling used in phone and data networks toconnect a device to a jack, and the cabling used in the ceilings/walls toconnect the jack to the local equipment closet. Different category cable sup-ports different network connection speeds - generally, the higher the value,the faster the service. A network connection is only as fast as its slowest link.Category 3 wiring can carry a maximum rate of 10 Mbps (megabits persecond), category 5 can support Fast Ethernet (up to 100 Mbps), category 5eand 6 have the potential to carry Gigabit (1000 Mbps) service. Category 6

B

C


Central Office

Centralized CallProcessing

CLEC

CO

Codec

Common ChannelSignaling (CCS)

Competitive LocalExchange Carrier (CLEC)

wiring is currently the standard for new data jack installations except in alimited number of locations on campus that currently cannot support it. Outletcolor indicates wiring: beige is category 3 wiring, black is category 5 wiring,blue is category 6 wiring.

See CO.

Refers to a processing construct where all call processing is performed at acentral site, or hub, and no call processing is performed at branch sites.

See Competitive Local Exchange Carrier.

Central Office. Local telephone company office to which all local loops in agiven area connect and in which circuit switching of subscriber lines occurs.Central office can also refer to a single telephone switch, or what is known asa "public exchange" in Europe.

Coder-decoder.1. A device that typically uses pulse code modulation to transform analogsignals into a digital bit stream, and digital signals back to analog.

2. In Voice over IP, Voice over Frame Relay, and Voice over ATM, a softwarealgorithm used to compress/decompress speech or audio signals.

A communications system in which one channel is used for signaling anddifferent channels are used for voice/data transmission. Signaling System 7(SS7) is a CCS system, also known as CCS7.

Created by the Telecommunications Act of 1996, a CLEC is a service providerthat is in direct competition with an incumbent service provider. CLEC is oftenused as a general term for any competitor, but the term actually has legalimplications. To become a CLEC, a service provider must be granted "CLECstatus" by a state's Public Utilities Commission. In exchange for the time andmoney spent to gain CLEC status, the CLEC is entitled to co-locate itsequipment in the incumbent's central office, which saves the CLECconsiderable expense.


Dark Fiber

DHCP

DID

Digital Signal Processor(DSP)

Direct Inward Dialing

Direct Outward Dialing(DOD)

Refers to unused fiber-optic cable. The dark strands can be leased or sold toindividuals or other companies who want to establish optical connectionsamong their own locations.

Dynamic Host Configuration Protocol. A TCP/IP protocol that enables PCsand workstations to get temporary or permanent IP addresses out of a poolfrom centrally-administered servers. Like its predecessor, BOOTP, DHCPprovides a mechanism for allocating IP addresses manually, automaticallyand dynamically, so that addresses can be reused when hosts no longer needthem.

For Cisco CallManager, a DHC server is queried by a telephone or gatewaydevice upon booting to determine network configuration information. TheDHCP server provides the device with an IP address, subnet mask, defaultgateway, DNS server, and a TFTP server name or address. With Cisco IPPhones, DHCP is enabled by default. If disabled, you must manually enterthe IP address and other specifications manually on each phone locally.

Direct Inward Dialing. A method of directly dialing the directory number of aCisco IP Phone or a telephone attached to a PBX without routing callsthrough an attendant or an automated attendant console, such as Cisco Webattendant. Compare to DOD.

A specialized digital microprocessor that performs calculations on digitizedsignals that were originally analog, and then forwards the results. The bigadvantage of DSPs lies in their programmability. DSPs can be used tocompress voice signals to as little as 4,800 bps. DSPs are an integral part ofall voice processing systems and fax machines.

See DID.

Direct Outward Dialing. The ability to dial directly from Cisco CallManager orPBX extension without routing calls through an operator, attendant orautomated attendant functions. Compare to DID.

D


Dual-Tone Multi-frequency(DTMF)

Dynamic HostConfiguration Protocol

ESN

Finger

Frame Relay

A way of signaling consisting of a push-button or touch tone dial that sendsout a sound consisting of two discrete tones that are picked up and interpret-ed by telephone switches (either PBXs or central offices).

See DHCP.

Emergency Service Number. Assigned to the subscriber's telephone numberin the tandem office translations. The ESN represents a seven digit numberby which the tandem office routes the call to the proper PSAP. PSAPs withALI capabilities also receive a display of the ESN information that showswhich police, fire and rescue agency serves the telephone number calling911. An ESN is a unique combination of police, fire, and rescue service forpurposes of routing the E911 call.

A program that goes to a computer running the finger daemon (service) andreturns information about a particular user, if available. Part of the informationdisplayed is the .plan and .project files. Some people update these files often,allowing others to find information about them easily. Originally the fingerclient was a UNIX program, but now versions are available for otheroperating systems.

ITU-T-defined access standard. Frame Relay services, as delivered by thetelecommunications carriers, employ a form of packet switching analogous toa streamlined version of X.25 networks. Packets are in the form of frames thatare variable in length with the payload being anywhere between zero and4,096 octets. Frame Relay networks are able to accommodate data packetsof various sizes associated with virtually any native data protocol.

E

F


Gatekeeper

Gateway

Gateway Controller

GigE

H.323

A component of the ITU H.323 "umbrella" of standards defining real-timemultimedia communications and conferencing for packet-based networks.The gatekeeper is the central control entity that performs managementfunctions in a Voice and Fax over IP network and for multimedia applicationssuch as video conferencing. Gatekeepers provide intelligence for the net-work, including address resolution, authorization, and authenticationservices, the logging of call detail records, and communications with networkmanagement systems. Gatekeepers also monitor the network for engineeringpurposes as well as for real-time network management and load balancing,control bandwidth, and provide interfaces to existing legacy systems.

The point at which a circuit-switched call is encoded and repackaged into IPpackets. A gateway is an optional element in an H.323 conference and bridgeH.323 conferences to other networks, communications protocols, andmultimedia formats.

Coordinates setup, handing and termination of media flows at the mediagateway.

Gigabit Ethernet, a transmission technology based on the Ethernet frameformat and protocol used in local area networks (LANs), provides a data rateof 1 billion bits per second (one gigabit). Gigabit Ethernet is defined in theIEEE 802.3 standard and is currently being used as the backbone in manyenterprise networks.

ITU-T standard that describes packet-based video, audio, and data confer-encing. Allows dissimilar communication devices to communicate with eachother using a standardized communications protocol. H.323 is an umbrellastandard that describes the architecture of the conferencing system, andrefers to a set of other standards (H.245, H.225.0, and Q.931) to describe itsactual protocol. For example, the Cisco IOS integrated router gateways useH.323 to communicate with Cisco CallManager. See also gateway.

G

H


H.323 Terminal

H.GCP

Hot Desking

Hoteling

ICM

IEEE

Incumbent LocalExchange Carrier (ILEC)

Endpoint on a LAN. Supports real-time, 2-way communications with anotherH.323 entity. Must support voice (audio codecs) and signaling (Q.931, H.245,and RAS). Optionally supports video and data e.g., PC phone, videophone,Ethernet phone.

Breaks up a gateway into a decomposed architecture whereby the mediagateway (MG), and the media gateway controller (MGC) are treated asseparate components.

Using a set of cubicles for mobile workers who come into the office from timeto time. It is similar to hoteling, but reservations are not required. Peoplecome in and sit down at the next available seat, plug into the network and goto work, which means a vice president might sit next to a junior trainee at anygiven time.

Using office space on an as-needed basis like a hotel room. Telecommutersreserve office space ahead of time for trips to the office.

Intelligent Contact Manager. The Cisco software system that implementsenterprise-wide intelligent distribution of multi-channel contacts (for example,inbound and outbound telephone calls, e-mail messages, Web collaborationrequests, chat requests) across contact centers. Cisco ICM software is anopen-standards-based solution that provides contact-by-contact pre-routing,post-routing, and performance-monitoring capabilities.

Institute of Electrical and Electronics Engineers. Professional organizationwhose activities include the development of communications and networkstandards. IEEE LAN standards are the predominant LAN standards today.

Typically the carrier that was granted the right to provide service as a resultof the breakup of AT&T. These providers are also referred to as RBOCs(Regional Bell Operating Companies) or Baby Bells.

I


Interactive VoiceResponse (IVR)

InternationalTelecommunicationsUnion (ITU)

Internet Engineering TaskForce (IETF)

Internet Protocol (IP)

IP

IP Contact Centers

IP Telephony

Interworking Function(IWF)

Links callers with information in databases. This technology allows callers tocomplete transactions or queries over the phone. Automatic SpeechRecognition (ASR) is fast replacing the DTMF method of activating IVRservices and is one of the most important recent innovations intelephony-based self-service.

An organization established by the United Nations to set telecommunicationsstandards, allocate frequencies to various uses, and sponsor trade showsevery four years.

One of two technical working bodies in the Internet Activities Board. It meetsthree times a year to set the technical standards for the Internet.

Internet Protocol. Messaging protocol that addresses and sends packetsacross the network in the TCP/IP stack, offering a connectionless internetwork service. To communicate using IP, network devices must have an IPaddress, subnet, and gateway assigned to them. IP provides features foraddressing, type-of-service specification, fragmentation and reassembly, andsecurity. Standardized in RFC 791.

See Internet Protocol.

A contact center that does not use circuit switching. All calls are IP orconverted from PSTN to IP. Also called: IPCC, IP-based Call Centers,Converged IP Contact Centers, and IP-based Contact Centers.

Technology that allows voice phone calls to be made over the Internet orother packet networks using a PC via gateways and standard telephones.

Provides the means for two different technologies to interoperate.


ISDN

IVR

Jitter

LAN

LATA

Layer 2 NetworkTechnologies

Layer 3 NetworkTechnologies

Integrated Services Digital Network. Communication protocol, offered bytelephone companies, that permits telephone networks to carry data, voice,and other source traffic.

See Interactive Voice Response.

A type of distortion caused by the variation of a signal from its reference thatcan cause data transmission errors, particularly at high speeds.

Local-area network. High-speed, low-error data network covering a relativelysmall geographic area (up to a few thousand meters). LANs connectworkstations, peripherals, terminals, and other devices in a single building orother geographically limited area. LAN standards specify cabling andsignaling at the physical and data link layers of the OSI model. Ethernet,FDDI, and Token Ring are widely used LAN technologies. Compare withMAN, VLAN and WAN.

Local access and transport area.

At this layer, data packets are encoded and decoded into bits. It furnishestransmission protocol knowledge and management and handles errors in thephysical layer, flow control and frame synchronization. The data link layer isdivided into two sublayers: The Media Access Control (MAC) layer and theLogical Link Control (LLC) layer. The MAC sublayer controls how a comput-er on the network gains access to the data and permission to transmit it. TheLLC layer controls frame synchronization, flow control and error checking.

This layer provides switching and routing technologies, creating logical paths,known as virtual circuits, for transmitting data from node to node. Routing andforwarding are functions of this layer, as well as addressing, internetworking,error handling, congestion control and packet sequencing.

J

L


LEC

Local Exchange Carrier(LEC)

Local Loop

Media Access Control(MAC)

MCU

Media Gateway

Media Gateway Controllers

Media Termination Point(MTP)

See Local Exchange Carrier.

A company that provides local telephone service.

1. The communication line between a telephone subscriber and the localexchange carrier (LEC) switching center.2. A local connection between an end user and a central office (CO) or endoffice (EO).

Lower of the two sub layers of the data link layer defined by the IEEE. TheMAC sub layer handles access to shared media.

Multipoint Control Unit. The combination of a multipoint controller and amultipoint processor.

A generic class of products grouped under the Media Gateway ControlProtocol (MGCP). A major function of the media gateway is simple IP/TDMconversion under the control of a soft-switch. Media gateways include, butare not limited to, the following types of equipment: standalone, server-basedgateways, RAS-based gateways, gateway switches, traditional CO switches,and ATM switches.

Also known as Call Agents. See Call Agents.

Media Termination Point. A virtual device that allows transfer, forward,conference, and hold features on any G.711 -law call between an IP Phoneand any H.323 gateway, gatekeeper, or client. A call using MTP will automat-ically convert A-law to -law (and vice versa), if required. As a Cisco softwareapplication, MTP installs on a server during the software installation process.

M


MEGACO

Metro-Ethernet

Media Gateway ControlProtocol (MGCP)

Multi-Protocol LabelSwitching (MPLS)

Multipoint Control Unit

Multi-Service Network

Network Appliance

A signaling protocol that enables switching of voice, fax and multimedia callsbetween the PSTN and next-generation IP networks, allowing dramaticgrowth and scalability of enhanced services. An updated and enhancedversion of MGCP (Media Gateway Control Protocol.)

Ethernet access and services across a MAN (metropolitan area network).Also called: Metropolitan Ethernet and MEN.

Enables external control and management of data communications equip-ment operating at the edge of multi-service packet networks (known as mediagateways) by software programs, which are known as "call agents" or "mediagateway controllers."

MPLS is a scheme typically used to enhance an IP network. Routers on theincoming edge of the MPLS network add an 'MPLS label' to the top of eachpacket. This label is based on some criteria (e.g. destination IP address) andis then used to steer it through the subsequent routers. The routers on theoutgoing edge strip it off before final delivery of the original packet. MPLS canbe used for various benefits such as multiple types of traffic coexisting on thesame network, ease of traffic management, faster restoration after a failure,and, potentially, higher performance.

See MCU.

Same as multiuse network. A network that handles data, voice, and othercapabilities simultaneously.

A typically inexpensive personal computer, sometimes called a thin client, thatenables Internet access and some business-related activities but lacks manyfeatures of a fully equipped PC, such as a hard drive or CD-ROM.Applications used on network appliances typically are housed on a Webserver accessed by the appliance. Network appliances are used to easeremote management and cut costs.

N


OSI

Packet

Packet Network

Private Branch Exchange(PBX)

Priority Queuing

Protocol

Open Systems Interconnection. The only internationally accepted frameworkof standards for communication between different systems made by differentvendors. Developed by the International Organization for Standardization,OSI is a model, not an active protocol. OSI organizes the communicationprocess into seven different categories and places these in a layeredsequence based on their relation to the user. The seven layers are: physical,data link, network, transport, session, presentation and applications.

Logical grouping of information that includes a header containing controlinformation and (usually) user data. Packets are most often used to refer tonetwork layer units of data. The terms datagram, frame, message, andsegment are also used to describe logical information groupings at variouslayers of the OSI reference model and in various technology circles.

Network that transmits data in packet-mode (data are broken up into packetsto be routed to their destination) as opposed to circuit-mode.

Digital or analog telephone switchboard located on the subscriber premises,typically with an attendant console, and used to connect private and publictelephone networks. A PBX is a small, privately owned version of the phonecompany's larger central switching office. It is connected to one or morecentral offices by trunks, and provides service to a number of individualphones, such as in a hotel, business, or government office. On a PBX, anoutside line is normally accessed by dialing an access digit, such as 9.

A priority queue is an abstract data type supporting the following twooperations: add an element to the queue with an associated priority; removethe element from the queue that has the highest priority, and return it.

A set of rules or conventions that govern the format and relative timing of datain a communications network. There are three basic types of protocols:character-oriented, byte-oriented, and bit-oriented. The protocols for datacommunications cover such things as framing, error handling, transparency,and line control. Ethernet is an example of a LAN protocol.

O

P


Proxy

PSAP

Public Switched TelephoneNetwork (PSTN)

QoS

RAID

Real-Time TransportProtocol (RTP)

Rich Media Conferencing

A device that relays network connections for other devices that usually lacktheir own network access.

Public Safety Answering Point, usually the police, fire and/or rescue groupsas determined by the local municipalities. A "ring-in" will not have ANI or ALIcapabilities, but just receives calls or transferred calls from another PSAP.

General term referring to the variety of telephone networks and services inplace worldwide.

Quality of Service. Measure of performance for a transmission system thatreflects its transmission quality and service availability.

Redundant Arrays of Independent Disks. A disk system with RAID capabilitycan protect its data and provide on-line, immediate access to its data, despitea single (some RAID storage systems can withstand two concurrent disk fail-ures) disk failure.

RTP is designed to provide end-to-end network transport functions for appli-cations transmitting real-time data, such as audio, video, or simulation data,over multicast or unicast network services.

Rich Media Conferencing is a term that is used to describe the integration ofvarious forms of media (such as audio, video and data) into one single'multimedia' conferencing environment. Previously we used these communi-cation applications in stand-alone environments, e.g. the phone for audiocommunication, the video for visual communication, and a web conferencingservice for simultaneous collaboration.

Q

R


Router

RTP

Selective Routing

Session Initiation Protocol(SIP)

Signaling Control Point(SCP)

Signaling Gateway

1. An interface device between two networks that selects the best route evenif there are several networks between the originating network and thedestination.2. A device that provides network management capabilities (e.g., loadbalancing, network partitioning, usage statistics, communications priority andtroubleshooting tools) that allow network managers to detect and correctproblems.3. An intelligent device that forwards data packets from one local areanetwork (LAN) to another and that selects the most expedient route based ontraffic load, line speeds, costs, or network failures.

See Real-time Transport Protocol.

The capability to route a call to the particular PSAP serving the addressassociated with the telephone number making the 911 call. Selective routingis achieved by building TN/ESN translations in the tandem central office.These translations are driven by the E911 data base which assigns the ESNto each telephone number based on the customer's address. Service orderactivity keeps the E911 data base updated. The E911 data base, in turn,generates recent change to the tandem office to update the telephonenumber/ESN translations in the tandem data base.

A signaling protocol for Internet conferencing, telephony, presence, eventsnotification and instant messaging. The protocol initiates call setup, routing,authentication and other features to endpoints within an IP domain.

An SCP is usually a computer used as a front end to a database system. It isan interface to telco databases, not usually to other, application-specificdatabases. Telco databases are usually linked to SCPs by X.25 links. TheSCP can provide protocol conversion from X.25 to SS7, or can provide directaccess to the database through the use of primitives which support accessfrom one level of protocol to another.

SS7-IP interface - coordinates the SS7 view of IP elements and IP view ofSS7 elements.

S


Signaling System 7

SIGTRAN

SIP

Skinny Station Protocol

SMDI

Soft-keys

SoftPhone

Soft-tokens

See SS7.

SIGTRAN (for Signaling Transport) is the standard telephony protocol usedto transport Signaling System 7 (SS7) signals over the Internet. SS7 signalsconsist of special commands for handling a telephone call.

See Session Initiation Protocol

See SSP.

Simplified Message Desk Interface. Analog data line from the central officecontaining information and instructions to your on-premises voice mail box. Arequired interface for voice mail systems used with Cisco CallManager. SMDIwas designed to enable voice mail integration services to multiple clients.However, to use SMDI, the voice mail system must meet severalqualifications, including providing database support for two PBX systemssimultaneously and IP network connectivity to the voice messaging systemwhile maintaining the existing link to the PBX. SMDI-compliant voice mailsystems must be accessible with a null-modem RS-232 cable and availableserial port.

On a Cisco IP Phone, buttons that activates features described by a textmessage. The text message is displayed directly above the soft key button onthe LCD screen.

Application that enables you to use a desktop PC to place and receivesoftware telephone calls and to control an IP telephone. Also allows for audio,video, and desktop collaboration with multiple parties on a call. Cisco IPSoftPhone can be used as a standalone application or as a computertelephony integration (CTI) control device for a physical Cisco IP phone. Allfeatures are functional in both modes of operation.

(1) In programming languages, a single element of a programming language.For example, a token could be a keyword, an operator, or a punctuation mark.(2) In networking, a token is a special series of bits that travels around atoken-ring network. As the token circulates, computers attached to thenetwork can capture it. The token acts like a ticket, enabling its owner to send


SS7

SSP

Switch

T.120

T.38

T1

TCP/IP

a message across the network. There is only one token for each network, sothere is no possibility that two computers will attempt to transmit messages atthe same time.

Signaling System 7. A telephone signaling system with three basic functions:supervising (monitoring the status of a line or circuit to see if it is busy, idle,or requesting service); alerting (indicating the arrival of an incoming call);addressing (transmission of routing and destination signals over the network).

Skinny Station Protocol. A Cisco protocol using low bandwidth messages thatcommunicate between IP devices and the Cisco CallManager.

Network device that filters, forwards, and floods pieces of a message(packets) based on the destination address of each frame. Switches operateat the data link layer of the OSI model. See also OSI.

An ITU-T standard (International Telecommunications Union) for documentconferencing. Document conferencing allows two or more people toconcurrently view and edit a document across a network.

Defines procedures for real-time Group 3 facsimile over IP network.

Trunk Level 1. A high-speed (1.544 megabits per second) digital telephoneline with the equivalent of 24 individual 64Kbps channels, which are joined viatime division multiplexing. A T-1 can be used to transmit voice or data, andmany are used to provide connections to the Internet. Also known as a DS1or Digital Signal 1.

Transmission Control Protocol/Internet Protocol. The two best-known internetprotocols, often erroneously thought of as one protocol. The transmissioncontrol protocol (TCP), which corresponds to Layer 4 (the transport layer) ofthe open systems interconnection (OSI) reference model, provides reliable

T


TDM

Telephony

Trivial File TransferProtocol (TFTP)

Toll bypass

Trunk

TTY

User Datagram Protocol(UDP)

transmission of data. The internet protocol (IP) corresponds to Layer 3 (thenetwork layer) of the OSI model and provides connectionless datagramservice. TCP/IP was developed by the U.S. Department of Defense in the1970s to support the construction of worldwide internetworks.

Time Division Multiplexing. A technique for transmitting a number of separatedata, voice, and video signals simultaneously over one communicationsmedium by quickly interleaving a piece of each signal one after the other.

Science of converting sound to electrical signals and transmitting it betweenwidely removed points.

A simplified version of the FTP, TFTP is an application that transfers deviceconfiguration files (.cnf files) to devices from a TFTP server.

A toll-free telephony call in which the relative locations of the two ends of theconnection would cause toll charges to be applied if the call was made overthe PSTN.

Physical and logical connection between two switches across which networktraffic travels. A trunk is a voice and data path that simultaneously handlesmultiple voice and data connections between switches. A backbone iscomposed of a number of trunks. See also CO.

A TTY is also known as a TDD (Telecommunications Device for the Deaf).

A connectionless messaging protocol for delivery of data packets. A simpleprotocol that exchanges datagrams without acknowledgements orguaranteed delivery, requiring that error processing and retransmission behandled by other protocols.

U


Unified Messaging

VLAN

Voice over InternetProtocol (VoIP)

Wide Area Network (WAN)

Wi-Fi

Wi-Max

An application that provides a single network-based access point from whichusers can manage all information and message types, using any number andvariety of access devices (PC, web browser, phone, etc.), from anywhere,and regardless of connection path (LAN, Internet, telephone). Unifiedmessaging solutions seamlessly integrate voice mail, e-mail, and fax in asingle e-mail inbox on one server. From a central digital store, all of thesemessage types are accessible via multiple devices and interfaces with aconsistent set of features and capabilities.

Virtual LAN. Group of devices on one or more LANs that are configured(using management software) so that they can communicate as if they wereattached to the same wire, when in fact they are located on a number ofdifferent LAN segments. Because VLANs are based on logical instead ofphysical connections, they are extremely flexible. See also LAN.

Technology used to transmit voice conversations over a data network usingthe Internet Protocol (IP). VoIP primarily builds on and complements existingstandards, such as H.323.

A communications network used to connect computers and other devicesacross a large area. The connection can be private or public.

Short for wireless fidelity and is meant to be used generically when referringof any type of 802.11 network, whether 802.11b, 802.11a, dual-band, etc.

A more powerful version of Wi-Fi that can provide wireless Internet accessover wider geographic location such as a city.

V

W

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May 2005 VoIP and IP TELEPHONY · VoIP and IP Telephony: Planning for Convergence in State...

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