Impact of cell discard strategies on TCP/IP in ATM UBR networks
Vincent Rosolen, Olivier Bonaventure, Guy Leduc · ORBi (University of Liège) · 1998
Keywords Simulation, performance, fairness, TCP/IP, UBR. 1 INTRODUCTION 2 CELL DISCARD STRATEGIES Several techniques have been proposed to improve performance in ATM switches. Namely, dropping policies such as Tail Drop, Drop From Front [Lakshman 96] and variants with relation to the data unit format (i.e. cell or frame) were developed early to help switches deal with congestion. All these methods were partially successful, in the sense that they did achieve acceptable performance on congested links, but lacked fairness when throughputs were analyzed. Further investigation on this issue led researchers towards schemes aiming at both levels of performance. 2.1 Early Packet Discard (EPD) EPD was first proposed in [Romanow 95], along with Partial Packet Discard (PPD), as a first notable improvement in cell discard policies. The idea behind EPD is that a discarded cell makes its corresponding packet incomplete, and therefore useless : cells from this packet continue to flow even thou...