Performance evaluation of frame discard strategies in ATM networks

Abstract

The flow of papers proposing new schemes to cope with congestion in networks continues unabated. In particular, as the deployment of ATM networks advances, effective congestion control is required to ensure that these networks can effectively provide the wide range of services that they promise. This paper will attempt to evaluate whether recently proposed algorithms are likely to be useful in practice using performance simulation and modeling methods. In order to achieve a higher efficiency it is possible to implement some additional mechanism to control cell dropping at the switch's buffers. One of the most popular drop strategies is the early packet discard, which drops the entire higher level data units when the buffer queue reaches a certain threshold level. Another mechanism is the partial packet discard, which if a cell is lost in case of congestion, discards all the subsequent cells belonging to the same packet. The aim of this paper is to investigate how switch buffer efficiency depends on the placement of the EPD threshold and on how cell dropping will occur, due to the level of the congestion. Two of the most relevant factors are the distribution of the packet size and the traffic distribution. It is particularly aimed at estimating the effects of recent congestion control schemes for ATM networks.