A COMPARATIVE STUDY OF HYBRID GIT-CSMA/CD WITH I-PERSISTENT CSMA/CD FOR BUS NETWORKS

Abstract

Local Area networks (LANs) have been widely used in data processing applications either to meet the communication requirements of large organisation or to enable distributed access by a large number of terminals to centralised computing systems. Most of LAN's uses . multiaccess channel as the basis of their communication. MAC protocols are widely classified into contention based protocol and collision Coy fora► 6cteed free protocols. .- protocols such as CSMA-CD works well under light traffic, but at heavy traffic increase in frequency of collisions degrades network performance. Collision free protocols like token ring have longer delays at low load, but efficiency improves as the traffic increases. In this dissertation a hybrid Group Implicit token CSMA/CD (GIT-CSMA/CD) access protocol is studied. This protocols aims to effectively combine the advantages of CSMA/CD and token passing protocols,like immediate access during idle periods, maximum throughput and bounded delay during peak load periods. The property of bounded delay makes it suitable for real-time networks. Operating features of the protocol is described together with its computer simulation. The result showing delay throughput characteristics are compared with 1-persistent CSMA/CD.