Algorithms for switch-scheduling in the multimedia router for LANs

Abstract

The primary objective of the Multimedia Router (MMR) [1] project is to design and implement a single chip router targeted for use in cluster and LAN interconnection networks. The goal can be concisely captured in the phrase ‘QoS routing at link speeds’. This paper studies a set of algorithms for switch scheduling based on a highly concurrent implementation for capturing output port requests. Two different switch-scheduling algorithms called Row-Column Ordering and Diagonal Ordering are proposed and implemented in a switch-scheduling framework which involves a matrix data structure, and therefore enables concurrent and parallel operations at high-speed. Their performance has been evaluated with Constant Bit Rate (CBR), Variable Bit Rate (VBR), and a mixture of CBR and VBR traffic. At high offered loads both these ordering functions have been shown to deliver superior Quality of Service (QoS) to connections at a high scheduling rate and high utilization.