Converged Networks - Recursos VoIPFigure 2: Migrating to Converged Networks To support the migration...

Contact Centers Unified Communication ServicesIP Telephony

C o n v e r g e d N e t w o r k s

White Paper

March 2003

T a b l e o f C o n t e n t s

S e c t i o n 1 : Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

S e c t i o n 2 : Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

S e c t i o n 3 : Converged Network Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

S e c t i o n 4 : Converged Network Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

S e c t i o n 5 : Converged Network Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

S e c t i o n 6 : Converged Network Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6 . 1 IP Telephony/Multimedia Communciation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

6 . 2 Unified Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6 . 3 Multimedia Contact Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

S e c t i o n 7 : Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

a higher plane of communication

1

S e c t i o n 1 : E x e c u t i v e S u m m a r y

Businesses today are faced with many evolutionary technologies. As Enterprises are evolving their IT infra-

structure to a common IP based network, also known as “converged networks,” IT professionals must

understand these evolutionary technologies and their implication to the bottom line in order to be

successful. The goal of this paper is to offer a technology overview of the converged networks. This paper

discusses the enterprise IT infrastructure evolution trend, key components and services of the converged

networks, and applications that are supported by the converged networks including IP telephony, multi-

media-contact center, and unified communications. This paper is complementary to the white paper titled

Converged Communications: Delivering Business Value Through IP Telephony in the sense that this

paper focuses on technology aspects of the converged networks while the other focuses on business value

of the converged networks.

S e c t i o n 2 : I n t r o d u c t i o n

Enterprises seem to be evolving now more than ever. Driven by the need to become more virtual and

global, we find that many enterprises are evolving their IT infrastructures in three phases1 as shown in

Figure 1. In the traditional phase, enterprises have separate infrastructures for voice and data networks,

with time division multiplexing (TDM) for voice and IP for data. This is where the majority of enterprises

are today.

In the converged networks phase, enterprises build out their IP networks to leverage a common infrastruc-

ture for both voice and data. The points of emphasis in this phase are on enhancing the IP network to make

certain it meets enterprise-class criteria, and improving its performance via QoS and reliability features to

enable real-time, mission-critical business and communication applications. Note that applications can be

in phase two, but linked to infrastructure that is still in phase one.

As enterprises become more distributed and business performance needs dictate enhanced end user

capabilities, converged communications applications will be deployed.

Communication without boundaries

1 Avaya white paper, “The Evolution to Converged Comunications .

Figure 1: Evolution to Converged Communications

When enterprises migrate from traditional to converged networks and then to converged communications, there

is increasing disaggregation and modularization of components and applications, with a corresponding

increase in flexibility and cost efficiency. As systems become more modularized, their services can be

deployed in more configurations. They become easier to integrate into heterogeneous and multivendor

environments, and can be distributed anywhere within the network. This increased level of reusability

gives enterprises more flexibility to create new, higher-value applications. This enables a dynamic service

creation environment that can be modified or customized as needed to meet the ever-changing needs of the

virtual enterprise. Avaya is taking the lead in disaggregating its software and systems into an open communication

architecture that will enable its customers to transition to converged communications.

Enterprises will evolve portions of their infrastructures from one phase to the next according to their

business needs and will often be in more than one of these phases at the same time. The majority of

enterprises today are transitioning between traditional and converged networks, with some leading-edge

enterprises starting to transition to converged communications. Due to the gradual nature of this migration, it

is essential that an enterprise deploys an architecture that is evolutionary enough to accommodate existing

infrastructures and investments, but extensible enough to provide a foundation for deployment of new applications

and services.

Increasing flexibility & cost efficiency of software applications

Incr

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rel

iab

ility

& r

ob

ust

nes

s o

ver

IP

ConvergedCommunications

� Federated applicationsintegratingcommunications andbusiness services

� Dynamic service creationenvironment

� Rich multimodal userexperience

� End point intelligencewith user control

� Focus on software, openserver, Internettechnologies &methodologies in multi-vendor environment

FederatedServices

Distributed Software

Converged Networks� IP infrastructure for voice

& data� Scaleable reliable call

processing

� Multimedia contact center� Multimodal portals� Separated

communicationsapplications to leverageIP infrastructure

� Build out of webinfrastructure

IP QOS

Modular Systems

Traditional� Separate voice

and datanetworks

� Call center� Voice messaging� Best effort IP

BestEffort

Integrated


2


3

This paper focuses on technologies and components enabling the second phase of the evolution —

Converged Networks. It describes key issues and benefits of the converged networks, services provided by

converged network and applications supported by the converged networks.

S e c t i o n 3 : C o n v e r g e d N e t w o r k O v e r v i e w

The initial driver for converged networks is often cost reduction. In fact, by leveraging the same infrastruc-

ture to carry voice and data traffic, enterprises can significantly reduce tariffs and can lower operational

costs by simplifying the operation, administration, and management (OA&M) requirements. Increasingly,

though, enterprises are transitioning to converged networks due to the ease with which new functionality

can be added and deployed to improve productivity for end users. There are two business models

enterprises can follow in transitioning to the converged environment: The Utility Model and The

Value-Added Model. In the Utility Model, an IT organization must:

• Satisfy the requirements of the majority of the company’s business and functional managers

• Have performance levels that are appropriate for the business requirements

• Have a cost structure that is low when compared to companies that provide a similar set of services at

analogous performance levels.

In the Value-Added Model, an IT organization must continually deploy some new functionality that helps

the company’s business and functional managers to achieve their goals. More detailed discussions on these

two models are covered in Converged Communications: Delivering Business Value Through IP

Telephony which is either available on www.avaya.com or can be obtained from your Avaya

representative or Authorized Business Partners.

Converged networks require that the IP infrastructure be enhanced with reliability and QoS features so that it

can support more business critical and real time transactions. Critical building blocks include fault

tolerant and redundant network designs with reliable network components (e.g., switches, routers,

gateways, VPN, feature servers), as well as the ability to support end-to-end IP-based differentiated

services by using congestion management, traffic policy and shaping, access control, and QoS signaling.

Figure 2: Migrating to Converged Networks

To support the migration to converged networks, Avaya has disaggregated its PBX, with embedded call

processing software and integrated communication applications, into three components (refer to Figure 2):

• IP QoS-enabled network components, including media servers, media gateways, VPNs, and LAN

switch, where some of the components support “hot standby” configurations.

• Scalable and reliable call processing software that can be distributed between headquarter and branch

offices, or among multiple sites, as necessary, to fit the needs of a virtual enterprise.

• Standalone applications — including contact center, unified communication, and IP telephony — that

support the same user capabilities over both IP based and TDM based network infrastructures, in a

heterogeneous multi-vendor environment.

This is the first step in Avaya’s evolution of its solution portfolio to a modular and open communication

architecture. Even at this first step, the benefits of modular systems can be realized. For example, the new

call processing software can be coupled with the appropriate combination of media servers and gateways

as needed by the various different sites in a virtual enterprise. In cases where it is imperative that a branch

office survives a link failure, it can be outfitted with the appropriate media server.


4


5

In the following sections, we will discuss converged network components, converged network service

(IP QoS), and converged applications in more detail. Security issues of the converged networks are

addressed in the Security in Converged Networks white paper which is either available on

www.avaya.com or can be obtained from your Avaya representative or Authorized Business Partners.

S e c t i o n 4 ; C o n v e r g e d N e t w o r k C o m p o n e n t s

Figure 3 shows an example of converged enterprise network.

Figure 3: Converged Enterprise Network

Key components of a converged network include core data networking components such as LAN switches,

WAN routers and converged telephony/multimedia components including endpoints, gateways, and

servers. Their functions are described as follows:

IPPhone

IPPhone

Branch OfficeBranch Office

HeadquartersHeadquarters

PSTN

VPN/Firewall

VPN/FirewallWireless

Access Pointwith VPNenabledclients

IPSoftphonewith VPN

client

Media ServerMedia Gateway

Media Server

IPPhone

IPPhone

WAN

ISP

ISP

Internet

Mobile WorkersMobile Workers

Notebook with VPN remoteClient and IP Softphone

TelecommutingTelecommutingWorkersWorkers

DSL orCable

VPN

PC

PC

withVPNclient

withVPNclient

MediaGateway

ApplicationServers

LAN switch

LAN switch


6

• LAN switches: A device that filters and forwards packets between LAN segments. LAN switches operate

at the data link layer (layer 2) and sometimes the network layer (layer 3) of the OSI Reference Model.

• Routers: A device that connects any number of LANs. Routers also allow remote offices to connect over

a WAN. Communicating layer 3 paths via routing protocols allows routers to select the best possible

path for traffic. Routers also provide traffic shaping and other QoS features that enhance multi-media

communication.

• VPN device: A networking device that implements encryption and other security mechanisms to permit

organizations to establish secure, end-to-end, private network connections over third-party networks,

such as the Internet or extranets. Some of these VPN appliances are capable of elementary QoS.

• Firewall device: A device designed to prevent unauthorized access to or from a private network.

Firewalls can be implemented in both hardware and software, or a combination of both.

• Wireless Access Point: A device that functions as a radio transceiver and bridge for wireless LAN clients

and also transfers data from the client radios to wired LAN.

• Endpoints and User Agents: In a general sense, an endpoint is a source and/or receiving side of media such

as audio or video. Examples of endpoints are a PC running an audio/video communication applica-

tion or an IP telephone. While this probably suggests that a person uses the endpoint, an endpoint can

be an automated device, such as a voice mailbox. The endpoint also terminates a signaling protocol,

such as SIP or H.323, and may be controllable from some application via an API.

A special type of endpoint is the conference bridge, also known as a mixer or Multipoint Conference

Unit (MCU). No user is associated with the conference bridge, but it acts like an endpoint.

• Gateways: A gateway provides the translation between two different networks. Such a gateway trans-

lates between the different bearer or media streams (for example, between a synchronous stream on a

DS0 in an ISDN and an asynchronous packetized stream in a packet network), and also between the

different signaling protocols (for example, between Q.931in an ISDN and SIP or H.323 in a packet

network). “Traditional” or “legacy” gateways are typically “single box” gateways, since they provide

all translation functions within a single physical box. The traditional gateway can be decomposed into

its functional parts: media gateway, signaling gateway, and media gateway controller.


7

• Servers: Many functions would logically reside in a central place, such as in a server. One such function

is known as a registrar (SIP) or a gatekeeper (H.323). This service allows an endpoint to register its

current location (i.e., it maps between an IP address and an alias address, such as a SIP URI). Other

functions can reside in a server as well, such as a feature server that provides a set of “call processing”

features. The feature server can provide a wide variety of features, and can be invoked in varying

degrees depending on the call. A simple feature server can act as a redirection server or a SIP proxy. A

more complicated server might provide group or contact center features.

Network components are the basic building blocks of the converged network. They need to be available

and reliable. One of the concerns on migrating to a converged environment is network availability and

reliability. Most customers require the network and systems to be always available and to work correctly.

This is especially the case for any communications concerning emergency or other mission-critical

applications. A reliable converged network requires redundancy and fault-tolerance to be built in the

network components as well as overall network design including WAN connections and power

considerations. “99.999% reliability” also involves issues like fast fail-over protocols and the ability to

down load code into a device without taking it out of service; also known as, hot swappable hardware

and software.

S e c t i o n 5 : C o n v e r g e d N e t w o r k S e r v i c e s

Network Services in this section refer to the capabilities or services that the network infrastructure can

provide to the applications that are running on the networks. One of the key network services in the

converged networks is the Quality of Service (QoS). In the converged network environment, networks are

required to serve as a transport for a variety of applications, including mission critical business applica-

tions such as Enterprise Resource Planning, delay-sensitive voice traffic, bandwidth intensive video and

eCommerce applications. These business applications have different requirements on network resources.

Applications such as voice have stringent delay requirements and can tolerate only minimal packet loss,

while others cannot tolerate packet loss but do not have tight delay requirements. To meet the different

needs of the business applications and provide different level of network services, Quality of Service (QoS)

functions are required. QoS functions here refer to a combination of different complementary technologies

that come together to enable the delivery of differentiated services in the converged network environment.

Most commonly used QoS functions are:


8

• Marking & Classification: Packet marking marks or colors packets according to policy and business rules.

Packet classification identifies and partitions the packets into different priority levels or classes of

service based on the value of one or more header fields, such as source address, destination address,

DS field, protocol ID, source port and destination port numbers, and other information such as

incoming interface. The output of the classifier is fed through a scheduler into the queuing system,

where different queuing strategies can be applied for congestion management purpose. Classification

typically takes place at the edge of network, either in the wiring closet or within the voice endpoints

themselves.

• Congestion Management: Congestion management involves packet scheduling and resource allocation. It

provides capability to control congestion by using queuing algorithms to sort and place the traffic onto

different queues and then determining how to serve the queues onto an output link based on certain

priority. Examples of these techniques include Priority Queuing (PQ), Weighted Fair Queuing (WFQ),

etc.

• Congestion Avoidance: Congestion avoidance techniques monitor network traffic loads in an effort to

anticipate and avoid congestion before it becomes a problem. Congestion avoidance techniques

involve a variety of packet dropping mechanisms, including Random Early Detection (RED) and

Weighted Random Early Detection (WRED).

• Policing and Shaping: Policing is to ensure traffic rate fit within a specified contract. Excess packets are

dropped or marked down to a lower priority to maintain network integrity. Traffic shaping buffers

traffic and distributes traffic peaks over time for smooth flows.

• Signaling: QoS signaling provides a way for an end station or network node to signal its neighbors to

request special handling of certain traffic. QoS signaling plays a key role in configuring successful

overall end-to-end QoS service across networks. Either in-band (packet coloring) or out-of-band

(RSVP) signaling can be used to indicate that a particular QoS service is desired for a particular traffic

classification.

• Call Admission Control: Accept or reject a traffic flow based on availability of network resources.

• Link Efficiency Mechanisms: Link efficiency can be used on a low speed link to improve the bandwidth

efficiency. Link efficiency mechanisms include: Compressed Real-Time Protocol (CRTP) and Link

Fragmentation and Interleaving (LFI).


9

QoS functions needs to be engineered end-to-end. Depending on the traffic load and congestion situation,

different QoS functions can be used at different parts of an enterprise network to achieve required

end-to-end performance. The commonly used QoS functions at endpoints, LAN, and WAN are described

as follows:

• QoS at Endpoints: QoS functions such as packet marking and simple queuing need to be supported, at

least, by voice endpoints with embedded L2 switch. Endpoints with advanced QoS capability such as

RSVP signaling have additional advantages of being able to reserve the network resources for the

applications in a RSVP-aware network.

• QoS at LAN: QoS functions in the LAN are recommended if real-time audio and video will be transported

on the LAN. In a properly designed network, LANs do not experience significant link congestion since

the amount of traffic is often low relative to the amount of bandwidth available. However, temporary

congestion may occur in the LAN routers/switches when multiple large file transfers temporarily

occupy LAN router/switch queues. This temporary condition can cause either delay variation to

become noticeable or voice/video packets to be dropped. In order to ensure that high-bandwidth

traffic bursts do not adversely affect voice or mission-critical applications, QoS mechanisms such as

congestion management (queuing) and congestion avoidance can be used.

• QoS in the enterprise WAN: QoS functions in the WAN are useful in optimizing expensive resources since

bandwidth on a WAN link is typically more limited. QoS functions on WAN include classification,

congestion avoidance, congestion management, policing, shaping, and link efficiency mechanisms. All

or some combinations of these mechanisms can be used together to improve link efficiency, reduce

delay and jitter for delay-sensitive applications.

QoS administration and management is also a critical area. Centralized policy based tool and management

functions can be used to control and administer QoS functions end-to-end across the network to ensure

consistent QoS policy enforcement.

Avaya’s MultiService Network Infrastructure solutions (MSNI) and Enterprise Class IP Solutions (ECLIPS)

are QoS enabled. By implementing advanced QoS functions in the switches, gateways, and endpoints,

Avaya provides end-to-end QoS capabilities for converged networks to deliver the required performance

on various applications.


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S e c t i o n 6 : C o n v e r g e d N e t w o r k A p p l i c a t i o n s

Voice and voice-enabled applications are one of the most critical business applications in a converged

network. Migrating traditional voice and voice-enabled applications onto a converged network holds the

promise of lower costs and the opportunity for new features and functionalities. This section focuses on

applications such as IP telephony, multi-media contact center, and unified communications.

6.1 – IP Telephony/Multimedia Communication

Key considerations in migrating voice/multimedia communication onto a converged network include

network and system availability/reliability, scalability, voice quality, telephony feature sets, security,

manageability, standards compliance, protocol interoperability, and migration path/investment protection.

The following subsections will discuss issues related to these areas, specifically; voice quality, converged

telephony systems, migration, and protocol interoperability such as running IP telephony over a VPN.

Security issues related to IP Telephony applications are addressed in the Security in Converged

Networks white paper which is either available on www.avaya.com or can be obtained from your Avaya

representative or Authorized Business Partners.

Voice Quality In the Converged Network

Voice quality can be affected significantly, and adversely, by packet delay, packet jitter, packet loss, echo,

and choice of audio codecs. They are discussed in the following2:

• Delay: refers to the amount of time that a voice packet takes from the sender to reach the receiver

including the time it takes to do the processing inside them. Sources of delay in the network can be

processing delay at codec, buffer/queuing delays that occur in switches and routers, and transmission

delay. Very good sound Quality is achieved with one-way delay of 0-150 msec (millisecond) from user

to user. Depending upon requirements longer delays may be acceptable.

• Jitter: refers to the variation in delay, which can lead to the perception of “choppiness” in speech. Jitter

is caused by a variety of network factors, including congestion, varying packet sizes, packet mis-order,

or packet loss. Engineering QoS at network components such as routers, switches and gateways to

give voice priority treatment and/or using a Jitter buffer, can mitigate jitter. A jitter buffer is designed

to smooth packet flow by holding incoming packets for a specified period of time before forwarding

them to the decompression process. However, in so doing, it can also add packet delay.

2 Avaya IP Voice Quality Network Requirements,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html

• Echo: is the reflection of an audio signal back to its source. The reflection can be caused by acoustic

reverberation, electrical cross-talk in telephones or facilities, and impedance mismatches in analog

telephone lines and trunks. The perception of echo is commonly described as the experience hearing

your own voice come back through the earpiece as incoming sound and is technically measured by

determining the delay of the echoed signal and the strength of the reflected signal.

• Packet loss: Loss of packets in the network could happen due to heavily loaded networks i.e., packets

may be dropped due to queue or buffer overload in the intermediate nodes (routers, switches etc.,) or

completely filled jitter buffer at the endpoints causing choppy sounding of conversation.

• Network Packet Mis-Order: Packets can arrive out of order if they are sent over different routes. This can

be a result of an intentional situation, such a load balancing, or an un-intentional situation such as

re-routing due to network congestion. Packets that arrive out of order are discarded if they arrive

later than the jitter buffer can hold them. In this situation, network packet mis-order becomes

equivalent to packet loss.

• Codec Selection: The choice of the appropriate type of codec is typically made as a trade-off between the

cost of bandwidth and the quality of the voice communications. Table 1 lists the common speech

coding standards, the bandwidth they require, and the Mean Opinion Score (MOS) associated with

each type of codec. The MOS is a well-established method of determining voice quality by ITU.

According to ITU a MOS of 4.0 or higher is needed for toll-quality voice. Note that the bandwidth

listed in Table 2 does not include overhead associated with protocols such as UDP, and RTP.

Standard Coding Type Bandwidth (Kbps) MOS

G.711 PCM 64 4.3

G.729 CS-ACELP 8 4.0

G.723.1 ACELP 6.3 3.8

MP-MLQ 5.3

Table 1: Comparison of Speech Codec Standards

Delay cannot be eliminated completely from a VoIP path as it includes the inevitable processing time in the

endpoints and the transmission time. However, delay, jitter, and packet loss can be reduced and controlled

by enabling appropriate QoS functions at networks as described in Section 5 and other techniques such as

jitter buffer, echo cancellation, and packet loss compensation at endpoints to further improve voice quality

in the converged networks.


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12

Converged Telephony Systems

There are a few architectural variations of converged telephony systems. The most dominant architectures

are IP-enabled or pure LAN-based (Pure-IP)3.

IP-enabled PBX: Figure 4 shows an example of an IP-enabled system at central site.

Figure 4: IP-Enabled PBX at Central Location

In this architecture a variety of network interface cards, including integrated gatekeeper/gateway

port circuit boards, are added to existing PBXs, enabling them to interface with other devices on an IP

network, such as IP phones and soft phones connected to local and remote LANs. The call-processing

software is embedded in the PBX. Communication applications are either embedded within the PBX or

standalone but communicate with the PBX via proprietary protocols over TDM connections.

Remote Site

Central Site

WAN

PSTNPBX

Call ProcessingServer

Circuit Switch

Port Cards/Gateways

RouterRouter

ApplicationServer

IP SoftPhone

DigitalPhone

AnalogPhone

IPPhone

IP SoftPhone IP

PhoneAnalogPhone

DigitalPhone

Gateway(Survivable)

IP-enabled PBX

3 IP LAN Telephony: The Technology Migration Imperative,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html


13

LAN-Based Telephony: In this architecture, illustrated in Figure 5, the call processing software is built on

standard hardware and runs a standard operating system. Applications can be either integrated or

separated from call processing software. The standalone applications communicate with call processing

via standard interfaces over IP infrastructure.

Media gateways in both architectures are used to provide inter-working with PSTN via either analog or

digital trunks and existing analog devices, such as fax machines and analog phones. The gateways can be

further decomposed into media gateway controller, media gateway and signaling gateway as specified in

the H.248/Megaco standard. This approach has some desirable attributes:

• Separation of application from hardware. Since hardware is separated from the application, it allows

the creation of very flexible systems. For example, it would be possible to add a media gateway to a

small or branch office to provide local survivable communications while maintaining the application

at a central location.

Figure 5: LAN-Based Telephony System

Remote Site

Central Site

IP WAN

PSTN


ApplicationServer

Router

IP SoftPhone

DigitalPhone

AnalogPhone

IPPhone

Router

IP SoftPhone IP

Phone AnalogPhone

DigitalPhone

Gateway

Gateway(Survivable)

AnalogPhone


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• Vendor independence – Implementation of product according to adopted standards allows mixing of

components to fit the unique requirements of any network. IT allows the enterprise to optimize

existing infrastructure investments.

Deployment/Migration: IP-enabled and LAN-based architectures offer different benefits and limitations. In the

IP-enabled architecture, the feature functionality, application support, and the reliability of the traditional

PBX are preserved. Customer’s existing traditional phones and port-cards can be reused. Therefore, this

approach offers enterprises maximum investment protection and the easiest path to migrate to the con-

verged environment. The LAN-based telephony approach offers several networking advantages. It allows

the use of a single cable plant that can scale with the network. This approach enables enterprises to

manage a single infrastructure as well as possibly combine the telecom and data IT departments into one.

The most common approach enterprises use today, as shown in Figure 6, is to deploy an IP-enabled PBX at

the central location to leverage the existing TDM infrastructure and a LAN-based PBX at new locations.

Figure 6: Deployment Scenarios

IP SoftPhone

Remote Site

Central Site

WAN

PSTNPBX


Circuit Switch

Port Cards/Gateways

Router

Router

ApplicationServer

IP SoftPhone

DigitalPhone Analog

Phone IP

Phone

IP SoftPhone IP

Phone AnalogPhone

DigitalPhone

Gateway(Survivable)


Router

DigitalPhone

AnalogPhone

IPPhone

Gateway

New Site

IP-enabled PBX


15

The Avaya ECLIPS portfolio supports both implementations. With the recently announced additions to the

ECLIPS portfolio, Avaya greatly enhanced its converged telephony offerings. With the introduction of the

two new media servers and new gateways, the ECLIPS portfolio has become far more modular. Virtually

unlimited scalability can be achieved easily by adding more local or remote media gateways.

The modularity of ECLIPS portfolio and Avaya MultiVantage™ Software solution increases the

opportunities for 3rd parties to develop applications that can be supported by the Avaya ECLIPS portfolio.

Avaya’s ECLIPS achieves up to five 9s availability4 in a converged environment by combining different

levels of redundancy with a distributed network architecture and comprehensive telephony survivability

at remote sites.

With its Distributed Networking architecture, Avaya can install an S8700 Media Server with its dual Linux

processors running Avaya MultiVantage Software at a central site and can serve remote sites over a

converged WAN. This use of centralized call processing and networked applications delivers complete

and consistent telephony features and applications across the enterprise.

With Avaya’s MultiVantage Software based solutions, an enterprise’s investment can be preserved. When

Avaya introduced the ECLIPS portfolio in the Fall of 2001, Avaya’s DEFINITY® Servers could be IP-enabled

by adding an IP telephony gateway card so small to medium sized locations could take advantage of the

Avaya™ IP600 Internet Protocol Communication System. In the latest release, that migration can be

extended to a full IP-centric configuration, while still preserving the original PBX investment. In fact the

capacity for a single server can be extended to support up to 36,000 endpoints of which up to 12,000

can be IP.

VoIP over VPN

VPN and Firewall technologies are an integral part for providing security for Enterprises. Enterprise com-

munications via VPN offers opportunity for cost saving, flexible communications, and simplified network

administration. However, IP Telephony over VPN/Firewall presents certain technical challenges. The most

important challenges include achieving compatibility between IP Telephony and security protocols. One of

the examples is the issue of IP Telephony with Network Address Translation (NAT) since most VPNs and

Firewalls embed a Network Address Translation (NAT) function.

4 Avaya™ IP 600 and DEFINITY® IP Solutions: Reliability and Availability,http://www1.avaya.com/enterprise/solutions/convergence/eclips/whitepapers/.html

NAT has difficulties with protocols that embed IP address information within the payload of the IP packet.

SIP and H.323 devices allocate ports dynamically (for reception of media over UDP), and then pass these

addresses within the protocol. A typical NAT device will not be aware of this, and their translated packets

will have conflicting addresses in the IP header and in the payload. If the far end device replies back to the

payload’s address, the packet is undeliverable. Two generally accepted solutions to this problem are to:

• Use IPSec Tunneling to tunnel the NAT sensitive protocol through the public network so NAT is never

applied to the NAT sensitive protocol.

• Use application-aware NAT devices, such as H.323 or SIP aware NAT that parse application specific

messages to find addresses.

When an enterprise uses non-overlapping IP addresses across their multiple locations, either site-to-site or

site-to-SOHO, IPSec Tunneling can be used to tunnel the VoIP traffic through the IP WAN. However, when

an enterprise uses overlapping IP addresses across their multiple locations, IPSec Tunneling cannot be used

since NAT cannot be avoided. An H.323- or SIP-aware NAT is required here.

Avaya’s award-winning VPN solutions have embraced these alternatives and support IPSec and three

types of NATs today and will support H.323-aware NAT soon.

Avaya’s ECLIPS portfolio also includes an additional solution that allows H.323 traffic NATed without

upgrading VPN/Firewall for some IP Telephony configurations. By implementing a patent-pending auto-

detection/auto-compensation method on IP telephony servers and voice endpoints, a voice endpoint can

detect whether NAT is H.323-aware or not and make correction based on the info provided by VoIP server.

If the NAT is H.323-aware, no action is taken. If the NAT does not support H.323, action is taken by VoIP

servers and endpoints to correct the situation. This solution provides investment protection for customers

who do not want to upgrade their VPN/Firewall to add a VoIP application across their multiple enterprise

locations.

6.2 – Unified Communication

Voice mail and e-mail are two seemingly omni-present communication applications in the enterprise. In the

traditional networks, voice and email are run on separate networks: voice network and data networks. As

enterprises are evolving to converged networks, a new model for enterprise communications is taking

shape. The new model promises to bring consistency and seamless communication capabilities to the

enterprise and its customers by integrating communication infrastructure that spans the enterprise’s

existing and future communication channels. The new model is called Unified Communication.


16


17

The basic building blocks for Unified Communication are:

• Multimedia Collaboration – for quick and easy voice, video and data interaction.

• Message Management – for simplified and integrated management of voice, fax, email and video

images.

• Contact Direction – for seamless access to integrated directories from anywhere and any device.

• Personal Assistant and Mobility Management – for setting personal rules for controlling how others find

me/hide me/reach me and for handling important messages.

Avaya’s Unified Communication offerings include traditional solutions such as voice messaging, unified

messaging, and audio and video conferencing, as well as new solutions that combine simplified voice,

video, and data collaboration. Avaya Unified Communication lets customers communicate within and

beyond their enterprise for better, faster decision-making and superior responsiveness to customers,

associates and suppliers.

Avaya Unified Communication Center (UCC) solutions that deliver seamless access via speech, Web, and

wireless to a suite of personal productivity tools including Avaya™ Contact Information Management,

Avaya™ Message Management, and Avaya™ Calling and Conference Management for the in-office and

mobile workers. Whether through a Web browser, a wireless device, or a speech command, Avaya Unified

Communication Center allows users to seamlessly access rich calling and conferencing capabilities for easy

collaborative working sessions. Avaya Unified Communication Center has quick and easy message

handling for effective message management, integrated access to directories and databases for contact and

information management, and virtual 24/7 assistance to calendars and tasks for increased personal

efficiency. The result? Facilitation of better, faster decisions for a more competitively differentiated

enterprise.

6.3 – Multimedia Contact Center

Businesses today are interacting with customers across more channels than ever before. More traditional

call centers are evolving to Multi-media Contact Centers to service interactions via email, Web, chat, and IP

telephony. Customers must be treated with consistent business rules, consistent service levels, and consis-

tent knowledge regardless of whether the channel of communication is traditional TDM-based telephone,

IP telephone or via one of the many other points of contact that customers are using on a daily basis.


18

In the Multimedia Contact Center, interaction with customers includes phone, Web, email, and fax, and

new channels such as VoIP and wireless are emerging rapidly. Providing consistent customer experiences

across all these channels requires an integration of channel technologies around a single customer view

with common business decision-making, routing, management and interaction delivery. The Avaya™

Multi-media Contact Center provides a fully integrated multi-vendor, multi-platform, multi-channel

solution. Avaya’s solution integrates best in class skills based routing algorithms, runs on industry

standard platforms, supports a variety of interaction over both IP and non-IP infrastructures, as well as a

heterogeneous PBX switching environment. Avaya can deliver the customer to where ever your agent is,

in whatever way the customer prefers and then provides the management tools to enable the management

that tomorrow’s complex geographically dispersed Multi-media Contact center require.

S e c t i o n 7 : C o n c l u s i o n

Converged networks involve many evolutionary technologies and applications.. Even though the list may

seem long, Avaya is committed to help enterprises make a smooth transition to Converged Networks by

maximizing ROI and providing extremely high quality, manageable solutions. The Avaya ECLIPS portfolio,

MultiService Network Infrastructure (MSNI), Unified Communication Solutions, and Multi-media Contact

Center solutions provide enterprises a smooth migration path to the converged environment today. Avaya

is committed to providing enterprises with solutions that create an infrastructure that is evolutionary

enough to optimize existing investments, but extensible enough to provide a foundation for deployment

for new applications and services.

L e a r n M o r e

For additional information on our IP telephony solutions, please contact your Avaya Client Executive,

Authorized BusinessPartner, or visit us at avaya.com/learnmore/ip. For more information about Avaya

and our other award-winning solutions, visit avaya.com.

avaya.com

© 2003 Avaya Inc.All Rights Reserved. Avaya and the Avaya logo are trademarks of Avaya Inc. and may be registered in certain jurisdictions. All trademarks identified by the ®, SM or TM are registered trademarks, service marks or trademarks, respectively, of Avaya Inc. All other trademarks are the property of their respective owners.Printed in the U.S.A.03/03 • Ef-LB1893

About Avaya

Avaya enables businesses to achieve superior

results by designing, building and managing their

communications networks. More than one million

businesses worldwide, including 90 percent of

the FORTUNE 500®, rely on Avaya solutions and

services to enhance value, improve productivity

and gain competitive advantage.

Focused on enterprises large to small, Avaya is a

world leader in secure and reliable IP telephony

systems, communications software applications and

full life-cycle services. Driving the convergence of

voice and data communications with business

applications – and distinguished by comprehensive

worldwide services – Avaya helps customers

leverage existing and new networks to unlock value

and enhance business performance.

reach

a higher planeof communication

ServicesIP Telephony Contact Centers Unified Communication

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