Feedback based flow control in ATM networks with multiple propagation delays

We consider a model comprising of a single bottleneck node/switch fed by multiple Markov modulated fluid sources and with significant and possibly different propagation delays. The amount of traffic released by the sources depends on its state as well as delayed feedback from the network. Such a source model allows us to capture ABR as well as VBR traffic types. We obtain analytical results for computing various performance measures associated with this model. Based on these analytical results, we study the performance of the feedback policy for two different delay classes. In the parameter regime investigated, we observe that while the sources with a smaller delay do better, they do not do significantly better. Moreover, the performance of the farther sources improves as the second set of sources is moved closer. Thus, what may be perceived as unfairness due to the difference in feedback delays should really be interpreted as the closer sources helping the farther sources while helping themselves