Implementation, performance analysis and testing of a datalink layer in a broadband LAN

Abstract

With the introduction of broadband networks new technologies such as optical networks, high speed switches, ATM/STM will be introduced. These changes in technology create other prior conditions for the network protocols. Therefore a critical examination of the present protocols and their use is necessary. Especially the datalink layer, which must provide certain services to the higher OSI layer and is directly influenced by the transmission medium. In this report the data link layer of the OSI model is examined. A data link peer protocol has been developed and tested as a signaling link in a broadband distributed local area network. With the LAPD protocol as a starting point a new efficient and robust protocol has been developed. The key aspects in the development were dynamic creation and releasing of the peer protocol and a minimum of state transitions to make a fast response possible for support of distributive services. To examine the efficiency and robustness of the data link layer the characteristics of the transmission medium have to be modeled. Causes of the bit errors are identified and two bit error models are given.