This paper proposes a mechanism for equation-based congestion control for unicast traffic. Most best-effort traffic in the current Internet is well-served by the dominant transport protocol, TCP. However, traffic such as best-effort unicast streaming multimedia could find use for a TCP-friendly congestion control mechanism that refrains from reducing the sending rate in half in response to a single packet drop. With our mechanism, the sender explicitly adjusts its sending rate as a function of the measured rate of loss events, where a loss event consists of one or more packets dropped within a single round-trip time. We use both simulations and experiments over the Internet to explore performance. We consider equation-based congestion control a promising avenue of development for congestion control of multicast traffic, and so an additional motivation for this work is to lay a sound basis for the further development of multicast congestion control.

In this paper, we propose simple models of TCP behavior in a differentiated services network. Congestion avoidance technique in TCP makes it difficult for flows to achieve performance goal in differentiated services network. Our models are developed to estimate TCP throughput as functions in terms of the reservation rate, the probability of packet drop and the round-trip time. We present several simulations to validate our models, and the results clearly show that the models estimate TCP throughput quite accurately in various situations. Keywords : Differentiated service, TCP modeling, TCP throughput. 1 Introduction Differentiated services architecture is defined for providing different levels of services for different users or applications to meet their specific requirements (either or both throughput and delay guarantees) [1, 3, 5]. To support service differentiation for individual or aggregated flows, the architecture provides a meter and a marker at the edges of the network and...

This paper proposes a mechanism for equation-based congestion control for unicast traffic. Most best-effort traffic in the current Internet is well-served by the dominant transport protocol, TCP. However, traffic such as best-effort unicast streaming multimedia could find use for a TCP-friendly congestion control mechanism that refrains from reducing the sending rate in half in response to a single packet drop. With our mechanism, the sender explicitly adjusts its sending rate as a function of the measured rate of loss events, where a loss event consists of one or more packets dropped within a single round-trip time. We use both simulations and experiments over the Internet to explore performance. We consider equation-based congestion control a promising avenue of development for congestion control of multicast traffic, and so an additional motivation for this work is to lay a sound basis for the further development of multicast congestion control. 1.