Wireless ATM
Adaptive Voice/Data
Networks

Implementation and Performance Analysis of ATM Adaptation Layer Type 2

Vishal Moondhra

Abstract

In the recent years, Asynchronous Transfer Mode has been used to implement high speed networks providing multi-gigabit services for multimedia applications. However, Mobile systems necessitate the adaptation of the ATM paradigm to low bandwidth, high frequency, noisy links which are expensive. ATM protocol aspects have thus been modified to accommodate these links and provide high utilization of the limited bandwidth. These links are characteristically wireless, with bandwidths in the several kilobits. In this project, one such modification of ATM, the ATM Adaptation Layer Type 2 was implemented and itís performance measured. The implementation used the Narrowband ATM protocol as a basis to implement and test the higher layers of the AAL2, along with a simple AAL2 Negotiation Protocol. The AAL2 protocol calls for multiplexing many low bit rate fixed length íchannelsí on a single ATM Virtual Connection, and the ANP is used to setup, monitor and tear down these connections. To test the protocol, voice channels were setup between two hosts on a narrowband network. The voice application used Sinusoidal Transfer Protocol to compress and decompress recorded voice.


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