Switch scheduling in the multimedia router (MMR)

The primary goal of the Multimedia Router (MMR) project is the design and implementation of a router optimized for multimedia applications. The router is targeted for use in cluster and LAN interconnection networks which offer different constraints and therefore differing router solutions than WANs. This paper describes and evaluates a switch scheduling algorithm based on a priority biasing scheme for dynamically updating the priorities of the connections established through the router. Unlike existing schemes that simply use the age of a flit as its priority, the novel feature of the proposed approach is that the priority is biased using the measured quality of service (QoS) values for the connection. Furthermore, the structure of the switch scheduling algorithm is motivated by opportunities for pipelined and concurrent operation so that scheduling decisions could be made at switching speeds. The performance of two of the many possible biasing functions is evaluated