On the queueing behavior of multiplexed leaky bucket regulated sources

The leaky bucket algorithm, which has been proposed as a monitor/enforcer in the rate-based management of bandwidth in high-performance, integrated packet communication networks, is considered. The effectiveness of the unbuffered leaky bucket algorithm in protecting the quality of service (QOS) experienced by connections passing through a common internodal link queue is studied. It is shown that excess traffic generated by a source can pass through the leaky bucket without marked or discarded and cause unacceptable packet delay/loss to other connections sharing the queue. It is also shown that average bursts that are larger, or average rate that is higher, than that assumed at connection establishment can deteriorate the queue performance even with the leaky bucket enforcing the agreed throughput QOS by discarding packets. On the basis of this analysis, a strategy for alleviating these problems is devised, namely, allocating network bandwidth above the leaky bucket permit rate and configuring the leaky bucket with a loss/mark probability greater than 10^-2