A performance simulation of local area networks using CSMA/CD and token bus protocols

Abstract

This paper presents performance results obtained by simulating the behavior of a local area network (LAN) based on the IEEE 802.2 Type 3 Logical Link Control (LLC) service. Two different Medium Access Control (MAC) protocols were used, the carrier sense multiple access with collision detection (CSMA/CD) bus and token bus. The LLC, placed above the MAC and independent of the MAC, provides for the reliable transfer of data across the physical link. The simulation model has been designed to evaluate the mean response time observed by the user of the LLC service by using a simulation tool called NETWORK II.5. Built-in access protocols from NETWORK II.5 were used to model the MAC methods directly. The simulated system was established through the hardware and software entities and the interactions of the modules that implement the operations of the designated service. It was found that the user's request frequency and the MAC protocols employed both contribute to the response time experienced by the LLC user.