N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 8 - Multiservice Networking Mechanisms: H.323, SIP, MGCP and Megaco                        Slide 1 of 70                                                                                                    ________________

Objectives:

This module provides an introduction to the mechanisms used for delivering voice, data and video services over a LAN, the PSTN and a Cable TV network. These mechanisms include: H.323 from the ITU, the Session Initiation Protocol (SIP) from the Internet Engineering Task Force (IETF), the Media Gateway Control Protocol (MGCP) from the IETF, the MEdia GAteway COntrol (MEGACO) protocol, a joint effort by the IETF and ITU-T working groups and the PacketCable Network-based Call Signaling (NCS) protocol and the Multi-Protocol Label Switching (MPLS).

Multiservice networking is emerging as an important issue for both enterprise and public service provider network infrastructures. The concept of multiservice networking is to provide voice, data and video services over a single platform using packet or cell technologies. The benefits of multiservice networking are reduced operational costs, higher performance, integration and control, faster new applications and service deployment.

The ATM, Frame Relay and IP technologies based networks are touted to provide multiservice networking. Most of the mechanisms are developed for dominant IP-based network. A multiservice mechanism has two components: a signaling mechanism and a transport mechanism for delivery of the media stream with the highest possible quality. The first component is defined by many signaling protocols like H.323, SIP, MGCP, MEGACO and NCSPacketCable. The second component for IP network is the Real-time Transport Protocol (RTP) with the Real-time Transport Control Protocol (RTCP) providing QOS information to the participants in the call.

The communications industry had three separate networks for voice, data and video transmission. The nature of these three types of information is unique, for example data is mostly non-real-time while voice and video is real-time. The real-time information attributes make it very difficult to transmit with non-real-time information over the same infrastructure. Real-time requires preference over the non-real-time information to provide quality service. Multi-Protocol Label Switching (MPLS) is one of the technologies which enables the prioritization of the information packets transmitted over an IP network.

Multiservice networking will enable emerging business applications, such as unified voice and e-mail messaging, computer telephony integration, desktop video streaming, video conferencing and web-based call centers, by supporting real-time and non-real-time traffic.

This module will cover:

1.0   The characteristics voice, data and video traffic

2.0   H.323 architecture

3.0   SIP architecture

4.0   MGCP architecture

5.0   Megaco architecture

6.0   NCS PacketCable architecture

7.0   QOS protocols (RTP, RTCP)

8.0   IP telephony

9.0    Evolution of the PSTN

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