Performance analysis of contention protocols for local area networks

This thesis involves the performance analysis of computer communication protocols in local area networks (LAN). The computer communication models discussed require the sharing of a single channel by a population of N distributed users. The set of rules and algorithms employed to share the channel is referred to as the multiple access protocol.; Three different LAN multiple access protocols are studied by stochastic modeling and analysis. The first one is a protocol which uses contention access to a ring topology network: the Contention Ring Protocol. The other two protocols are developed based on a popular LAN protocol, called Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which has been used on Ethernet. One of these is an enhanced CSMA/CD protocol for real time transmission which is called CSMA/CD with Reservation, and another protocol is an Integrated Real Time and Nonreal Time Transmission Protocol. Both these protocols provide alternatives for the delivery of time critical messages within delay constraints, which is considered as an important performance criterion in the design and management of computer communication networks in the computer integrated manufacturing (CIM) environment.; For the contention ring protocol, expressions for the throughput and delay are developed using a renewal reward argument. The performance of the contention ring is then compared to that of CSMA/CD, the token ring and the token bus protocols. (The token bus is the protocol used in Manufacturing Automation Protocol (MAP.) It is shown that the contention ring combines many best features of these popular local network protocols.; The CSMA/CD with Reservation protocol is designed for real time transmission (voice, video, graphics, etc) by Ethernet type networks. The analysis is based on a semi-markov process built from the protocol. The analytical results show the throughput and delay of the protocol and the effect of the message size on performance of the protocol. The environment in which this protocol can be applied is studied. It also shows that CSMA/CD protocol can be considered as a special case of CSMA/CD with Reservation.; The integrated protocol combines CSMA/CD and CSMA/CD with Reservation in one protocol for both real time and non real time (data) transmission. This protocol is a variation on a protocol proposed by N. F. Maxemchuk. Markovian models are developed for the analysis of the protocol. The numerical analysis provides a tradeoff of performance between real time transmission and non real time transmission and also provides a control of the system.