Towards building H.323-aware 3G wireless systems : control loops in H.323-based multimedia networks

Dissertant

al-Maghraui, Kawthar

Thesis advisor

Rashidi, Taj al-Din

University

Al Akhawayn University

Faculty

School of Science and Engineering

Department

Computer Networks

University Country

Morocco

Degree

Master

Degree Date

2001

English Abstract

Third Generation ^اآطهe Systems are required to support Multimedia applications with high quality standards.

^0$ is a major issue in both wireless networks and multimedia systems, such as H.323 multimedia networks.

Both 3G wireless networks and H.323-based netwo^s use consol loops.

The former use low-le^el open and closed control loops to maintain س quality, while the latter tise out ofband channel signaling to provide adaptation to fluctuating network conditions and a robust transmission of real-time media streams.

However, v^ much like signaling in TCP (Transmission Control Protocol), H.323 signaling was tailored for ^^ed networks and is expected to su^ ^om the wireless intrinsic characteristics.

A though understanding of H.3^3 control loops would lead to optimising wireless lin^s for a multimedia environment, and to building H.323-aware/multim^a-aware Third Gene^^tion Wireless systems capable of playing an active role in the end to end H.323 signaling by intelligently forwaFding/changing/spoofmg control H.323 pack^s.

In H.323 ne^orks, RTF/RTCP (the real time protocol and the real time control protocol) are the ^ajor means used to carry both mu!tim<^ia and cont^>l packets.

QoS is assessed using RTCP packets; the control protocol desired to work in conjunction with RTP.

RTCP packets carry control information that helps in providing a variety of se^ices such as QoS monitoring and cong«؛tion control, [n RTP sessions, receivers periodically send RTCP packets to convey feedback on quality of data delivery a^ info^ation of membership.

Both the receiver and the sender use these reports for link adaptation and transmission adjustment.

H.245 is another sibling proocol used in H.323 ne^orks to cope with fluctuating network condition.

Most of the adaptation events are triggered by congestion, which is heavily relate to packet loss in fixed networks.

However, Cong^tion is not nec^sarily related to packet loss in a wireless environment.

Therefore, new adaptation schemes need to be devised in a wirel^ link to support H.323-based multimedia transmission.

This thesis 1.

surveys the main control loops in the H.323 multimedia applications, 2.

identifies the wire^s network events that might trigger them, and 3 suggests a filter architecture to adapt the different identified control loops to the wireless link.

To observe and analyze the main control packets that are exchanged d^ng an H.323 session, an H.323 Sniffer was implemented.

Its main task is to sniff and decode the various protocol messages on the fly, and detect the sender and receiver reports carried by the RTCP and the H.245 control messages for o^ine analysis of the correlation with the lower level control loops.

The Sniffer was inte^ated with a QoS enabled Universal Mobile Telecommunication System (UMTS) demonstrator that simulate a Third Generation Wireless link with QoS provisioning, developed as pa^ of a joined project between Alakhawayn University and Lucent Technologies.

Main Subjects

Telecommunications Engineering

Topics

• Radio
• Quality assurance

No. of Pages

102

Table of Contents

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-644991