Using dynamic weights for improving fairness in the ATM ABR service

Traditional switch algorithms in asynchronous transfer mode available bit rate networks fail to achieve desired (fair) bandwidth allocations, which are based on connection weights. Active fairness substantially improves fairness by using two sets of weights at each link. The first set is the same as that used in traditional schemes, which represents the relative bandwidth allocation desired out of the available bandwidth at the link. If these weights are used directly in bandwidth allocation, the actual proportion of the bandwidth utilized by an individual connection can deviate substantially due to factors such as the number of links traversed by the connection, its round-trip propagation delay, etc. In order to take into account these factors, the second set of weights is adjusted repeatedly, and is used directly in bandwidth allocation. Significant fairness improvement due to active fairness is demonstrated through simulations involving bursty background traffic, network bottlenecks, dynamic VC mixes and different fairness definitions