Congestion Control in ATM Networks Performance of BECN Scheme Implemented in 'C'

摘要

Congestion in a packet switched networks is a condition in whichrnperformance degrades due to saturation of the network resources such asrnavailable communication links, processor speed and buffer capacity. Adverserneffects resulting from such congestion are unacceptable delays, wastage ofrnsystem resources and possibly total network failure. The problem of congestionrnbecomes critical in Asynchronous Transfer Mode(ATM) networks due to diversernservice requirements, high link speed and various characteristics of traffic. ThernATM network has to provide guaranteed service to real-time applications suchrnas voice and video. It accommodates non real- time application such as data withrnAvailable Bit Rate (ABR) services.rnThe Preventive congestion control scheme takes necessary action inrnrestricting admission of calls to the network. In this the performances degradernfor data application due to its bursty nature. In reactive scheme, dynamicrnregulation of cell emission rate of various sources is achieved using feed backrnfrom the networks. This is more suitable for bursty data services.rnThis paper develops an analytical model based on Discrete timernMarkov chain and is applied for uniform and bursty traffic. The BackwardrnExplicit Congestion Notification (BECN) scheme simulation model is thenrncompared with analytical model. It has been implemented using C.