Dynamic behavior of slowly-responsive congestion control algorithms

The recently developed notion of TCP-compatibility has led to a number of p roposals for alternative congestion control algorithms whose long-term thro ughput as a function of a steady-state loss rate is similar to that of TCP. Motivated by the needs of some streaming and multicast applications, these algorithms seem poised to take the current TCP-dominated Internet to an In ternet where many congestion control algorithms co-exist. An important char acteristic of these alternative algorithms is that they are slowly-responsi ve, refraining from reacting as drastically as TCP to a single packet loss. However, the TCP-compatibility criteria explored so far in the literature c onsiders only the static condition of a fixed loss rate. This paper investi gates the behavior of slowly-responsive, TCP-compatible congestion control algorithms under more realistic dynamic network conditions, addressing the fundamental question of whether these algorithms are safe to deploy in the public Internet. We study persistent loss rates, long- and short-term fairn ess properties, bottleneck link utilization, and smoothness of transmission rates.