A scheduling scheme to improve QoS provisioning for IP traffic

Abstract

Output Queuing (OQ) and Input Queuing (IQ) are the two basic queuing strategies implemented in routers. IQ has been identified as the simplest and the most scalable. However, IQ achieves only 58.6% throughput due to the Head Of Line (HOL) blocking effect. The Virtual Output Queuing (VOQ) strategy is a proffered solution to the HOL blocking. It has been shown that VOQ can achieve a 100% throughput with an effective scheduling algorithm. This paper proposes a Multi stage Queuing and Scheduling strategy which implements VOQ at the input and OQ at the output of the router. The scheduling algorithm for the VOQ proposed in this paper is an Iterative Probabilistic Scheduling.