Competitive Buffer Management for Shared-Memory Switches
We consider buffer management policies for shared memory switches. We study the case of overloads resulting in packet loss, where the constraint is the limited shared memory capacity. The goal of the buffer management policy is that of maximizing the number of packets transmitted. The problem is online in nature, and thus we use competitive analysis to measure the performance of the buffer management policies. Our main result is to show that the well-known preemptive Longest Queue Drop (LQD) policy is at most 2-competitive and at least root 2-competitive. We also demonstrate a general lower bound of 4/3 on the performance of any deterministic online policy. Finally, we consider some other popular non-preemptive policies including Complete Partition, Complete Sharing, Static Threshold and Dynamic Threshold and derive almost tight bounds on their performance.
buffer management shared memory competitive analysis