Buffered and Unbuffered Leaky Bucket Policing: Guaranteeing QoS, Design and Admission Control

Traffic shaping and smoothing using buffers or leaky buckets does not necessarily improve Quality of Service (QoS). In fact there is a trade-off between controlling user traffic and guaranteeing QoS to the users. We consider the first two stages (source node and border node before entering a network cloud) of an end-to-end QoS problem and assume that the QoS requirements across each of the two stages are given. We formulate and solve a mathematical programming problem to select optimal leaky bucket parameters that would enable high-speed telecommunication network providers to optimize traffic policing subject to guaranteeing a negotiated Quality of Service requirement across the first stage namely the source end. We address both the buffered and unbuffered leaky bucket cases where using fluid models we characterize the output process from the leaky buckets for general traffic sources. Using the optimal leaky bucket parameters and output characteristics (effective bandwidths in particular), we solve design and connection admission control problems given QoS requirements at the second stage, namely the border node.