on "Congestion Avoidance and Control [2]"

The paper describes a congestion avoidance/control algorithm which has following features:

1. a connection re/starts slow, packet transmission rates starts low and then gradually increases, until such time the connection achieves its state of 'equilibrium'. This prevents the connection from sending big bursts of packets which makes it prone to failure because of constant packet retransmissions.

2. has a 'better' round-trip time variance estimation, which allows it to estimate a more realistic retransmit timeout interval, rto, for succeeding packets. This leads to the variability of the RTT variance used of the rto computation with respect to the medium of communication i.e. satellite links, which leads to increase in performance.

3. when congestion really happens, it employs an exponential retransmit timer backoff, which allows the system to really come into its normal state, no matter what.

4. for congestion avoidance, it uses an increase/decrease algorithm with additive increase and multiplicative decrease components. Unlike in [1] which uses a binary feedback mechanism (incorporated as a bit information in the packet header) in determining the state of the system, their algorithm depends on some assumptions about the inherent properties of "lost packets". That is, lost packets are lost essentially because, the network is congested. So if a connection experiences lost packets, this means that the network is experiencing congestion and it should decrease its load. On the other hand, if the connection continuously receives ACKs, then that means it can try increasing its load. To achieve fairness, the gateway would just have to dropped packets coming from mis-having (abusive) hosts, which in turn would 'trick' the host into believing that the network is experiencing congestion, thus have to decrease its load. Just curious, did this solution work? I still prefer [1], in terms of the feedback mechanism.

Ref:

[1] D.-M. Chiu and R. Jain, "Analysis of the Increase and Decrease Algorithms for Congestion Avoidance in Computer Networks", Computer Networks and ISDN Systems, Vol. 17, 1989, pp. 1-14.

[2] V. Jacobson, "Congestion Avoidance and Control", SIGCOMM '88, Sept. 1988, pp. 314-329.