Improving fairness of long VCs using active fairness in the ATM ABR service

The fair distribution of bandwidth to different connections is an important issue in the available bit rate (ABR) service in asynchronous transfer mode (ATM) networks. Traditional schemes fail to achieve desired bandwidth allocations, which are generally based on connection weights. This paper presents a new scheme called active fairness which substantially improves fairness in bandwidth allocations. Contrary to the single set of weights used in traditional schemes, active fairness maintains 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. Simulations under bursty background traffic and a bottleneck scenario demonstrate the effectiveness of active fairness