On the excess bandwidth allocation in ISP traffic control for shared access networks

Current practice of shaping subscriber traffic based on token bucket by Internet service provider (ISP) allows short-term fluctuations in its shaped rate and thereby enables a subscriber to transmit traffic at a higher rate than a negotiated long-term average. The traffic shaping, however, results in significant waste of network resources, especially when there are only a few active subscribers, because it cannot allocate excess bandwidth to active subscribers in the long term. In this letter we investigate the long-term aspect of resource sharing in ISP traffic control for shared access networks. We discuss major requirements for the excess bandwidth allocation in shared access networks and propose ISP traffic control schemes based on core-stateless fair queueing (CSFQ) and token bucket meters. Simulation results demonstrate that the proposed schemes allocate excess bandwidth among active subscribers in a fair and efficient way, while not compromising the service contracts specified by token bucket for conformant subscribers.