Solving Capture in Switched Two-Node Ethernets

It is well known that the Ethernet medium access control protocol can cause signiicant short-term un-fairness through a mechanism known as the Capture EEect, and that this unfairness condition is worst in heavily loaded Ethernets with a small number of active nodes. Recently, Ramakrishnan and Yang proposed Capture Avoidance Binary Exponential Back-oo (CABEB) to provide 1-packet-per-turn round robin service in the important special case of a 2-node collision domain. In this paper, we introduce an equal time round-robin scheme, in which only one node needs to be modiied. In our scheme, the modiied node maintains a local copy of the attempts counter of the other node. It uses this information to trigger switching its medium access policy between the two extremes of aggressively persistent and completely passive. As a result , the modiied node can control the actions of the other node in such a way that both enjoy fair, low delay , round-robin access to the shared channel.