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Identifying Design Considerations for Voice Services

Identifying Voice Networking Considerations

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-1

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Separate Voice and Data Networks

Companies want to reduce WAN costs by integration. Data is primary traffic on many voice networks. PSTN architecture is not flexible enough. PSTN can not integrate voice, data, and video.
? 2007 Cisco Systems, Inc. All rights reserved. DESGN v2.0—7-2

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Example: Voice over IP

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-3

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Example: IP Telephony

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-4

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Introducing H.323
ITU-T standard Describes packet-based video, audio, and data communication across packet-based networks

Provides session setup, monitoring, and termination
Refers to a set of other standards: – H.225 (Q.931): Call signaling – H.245: Capability negotiation and media stream management

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-5

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

H.323 Components

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-6

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Example: H.323 Components and Their Interactions

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-7

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

The Importance of a Gatekeeper

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-8

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

IP Telephony Components

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-9

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Design Goals of IP Telephony
To use end-to-end IP telephony between sites with IP connectivity To make IP telephony widely usable To lower long-distance costs To make IP telephony cost-effective To provide high availability of IP telephony To offer lower total cost of ownership and greater flexibility To enable new applications on top of IP telephony via third-party software To improve remote worker, agent, and work-at-home staff productivity To facilitate data and telephony network consolidation

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-10

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Single-Site IP Telephony Design

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-11

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Multisite WAN with Centralized Call Processing Design

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-12

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Multisite WAN with Distributed Call Processing Design

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-13

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Call Control and Transport Protocols
Voice call control functions: – Q.931 call setup signaling – H.245 call capability control – RAS signaling – RTP Control Protocol (RTCP)

Voice conversation:
– Real-Time Transport Protocol (RTP)

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-14

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

SCCP Control
SCCP is a client-server protocol.
SCCP clients register with Cisco Unified CallManager to receive their configuration information. Media connections between SCCP clients use RTP.

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-15

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

SIP Control
SIP is a peer-to-peer protocol.
SIP user agents communicate with SIP proxy server. SIP phones can register with Cisco Unified CallManager.

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-16

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

MGCP Control
MGCP is a client-server protocol. MGCP gateway translates between endpoints and IP phones. Call agents control MGCP endpoints.

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-17

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

Summary
Business needs are driving the need for unified voice and data networks not on the PSTN. The H.323 standard is a foundation for audio, video, and data communications across IP-based networks, including the Internet. IP telephony refers to communication services and voice, facsimile, and voice-messaging applications that are transported via the IP network rather than the PSTN.

Voice communication over IP relies on control protocols such as H.323, SCCP, SIP, and MGCP.

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-18

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.

? 2007 Cisco Systems, Inc. All rights reserved.

DESGN v2.0—7-19

The PDF files and any printed representation for this material are the property of Cisco Systems, Inc., for the sole use by Cisco employees for personal study. The files or printed representations may not be used in commercial training, and may not be distributed for purposes other than individual self-study.


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