Performance analysis of interconnected CSMA/CD local area networks

Abstract

The performance analysis of an interconnected system, consisting of M CSMA/CD (carrier sense multiple access with collision detection) local area network (LAN) segments using an M-port bridge, is presented. Each LAN segment consists of a finite number of identical stations, each having a unity buffer capacity. The bridge buffer capacity is greater than unity. The performance of such a system is analysed for the following two cases: (a) the bridge acting as a regular station, and (b) the bridge having a higher priority than the stations (i.e. performing exhaustive service. The method proposed for the analysis is based on the decomposition of the interconnected system into M consistent but otherwise independent asymmetric LANs. Each LAN segment is exactly analysed. Then, the performance of the interconnected system is found using the exact analysis of each LAN segment and approximating the inter- LAN traffic by a Bernoulli process. This leads to an iterative method, where the performance of each LAN segment is evaluated in turn, until convergence.