BAI613

Module 2 - Voice over IP Technology

Module Objectives1. Describe the benefits of IP

Telephony/Packet Telephony/VoIP over traditional telephone systems

2. Analyze some VoIP Applications such as Packet Telephony Call Centers, Service Provider Calling Card applications

Module Objective 1

Describe the benefits of IP Telephony/Packet

Telephony/VoIP over traditional telephone

systems

Separate Voice and Data Networks

Benefits of IP Telephony/Packet Telephony/VoIP over traditional

telephone systems Monetary SavingsTCO is lower (over a longer period of

time). Short term savings might not be

substantialConsolidation of network infrastructure,

staffing, and Service ProviderNew or Next-Generation Applications

Key Benefits of VoIP (contd.)

Easier Moves, Adds and Changes (MACs)

Dynamic Host Configuration Protocol (DHCP) based IP configuration

E.G. on CCM, profiles setup for phones based on MAC addresses

Key Benefits (contd..)

One Information Services (IS) department for both voice and data networks

Common infrastructure Additional tools not needed

Unified Messaging – Key benefit, Voicemail, Videomail and email in the same inbox. One location for checking your messages.

IP Telephony Advantages

IP Telephony AdvantagesConverged VoIP Network – A more efficient solution

Difference Between Converged Technologies

Voice Over Packet Transporting circuit voice over

another technologyCould be VoIP, VoFR, VoATM

LAN Telephony Telephony on a data network using

Layer 2 only (Ethernet)

Voice over Frame Relay

Voice over ATM

Voice over IP (IP Telephony)VoIP, also referenced as IP telephony when

integrated with IP-based signaling and call control, is how almost all new deployments are being implemented.

VoIP provides transport of voice over the IP protocol family. IP makes voice globally available regardless of the data link (Ethernet, ATM, Frame Relay) protocol in use.

Enterprise IP Telephony vs Internet Telephony

Internet Telephony uses IP but uses a public infrastructure (i.e. Internet) The Internet is unmanaged and not engineered for voice

and therefore cannot offer any type of SLA. The common result is poor voice quality

Enterprise IP Telephony is managed and engineered for voice offering a high quality network in which to transport voice. (How to do this will be learned in Topic 4)

However, industry has and continues to re-engineer the Internet in order to carry converged applications

Packet Telephony Call centersChallenges faced by Circuit Switched Call

centers:Unable to grow in smaller chunksTelecommuting expensive Many toll-free numbers Misrouted/rerouted calls Multiple centers Percentage distribution/overflow routingEmployee turnover

Module Objective 2: Analyze some VoIP Applications such as Packet Telephony Call Centers and Service Provider Calling Card Application

CSCC Challenges (Contd.)

Seasonal staffing needs Inconvenient busy hours Regional call-center talent - The CSCC technology addresses

some of the challenges above but Packet based call centers is the solution

CSCC Setup

Packet Telephony Based Call Centers

Click to talk

Service Provider Calling Card Case Study

The following list breaks down the call-flow of a pre- or post-paid call through an IP network:

Subscriber dials local phone number of service provider (call leg A).

Subscriber gets a second dial tone and is prompted to enter the destination phone number, account number, and password if calling away from home.

Call is completed to the destination phone (call legs B and C).

Calling Card Study

Calling Card Component Details

Calling Card Call Flow

1. The subscriber calls the local access number for the gateway.

2. The gateway queries the RADIUS server with the Automatic Number ID (ANI, or caller ID) of the caller.

3. The RADIUS server looks up the ANI to verify that the caller is a subscriber and then sends a message to the gateway to authenticate the user.

Calling Card Call Flow(1)

Calling Card Call Flow (2)

4. The user enters the destination phone number.

5. The gateway consults the gatekeeper on ways he can route the call.

6. The gatekeeper looks up the E.164 address against a table and sends the gateway the IP address of the destination gateway.

Calling card Call Flow(3)

Calling card call flow (4)

7. The originating gateway places an H.323 call across the IP network to the destination gateway.

8. The destination gateway places a PSTN call to the destination phone.

9. The gateways send start/stop records to the RADIUS server for billing.

Calling Card Call flow (5)

ACME Case Study (1)

ACME – Voice and Data Network

ACME Case Study (Present Network)

ACME Converged Network

ACME Cost Savings Phones use DHCP and keep phone numbers regardless of

physical location. Cabling to the desktop is easier (everything is Ethernet). Call appearance remains the same whether the user is at

home or at work. This enables fully transparent telecommuting.

The call-processing engine is now on a standard platform, which provides the enterprise network with greater flexibility.

Cisco's Call Manager is actually configurable through Hypertext Markup Language (HTML), which simplifies administrative overhead as well as PBX administration.

Cisco's Call Manager can also support other standards-based interfaces such as Station Message Desk Interface (SMDI) for an interface into a legacy PBX. As an example, you can use this interface to illuminate the message-waiting light.

Reading

Chapter 6 of textbook