R2: A Damped Adaptive Router Design

. R2 is an attempt to create an interconnection component that provides reliable packet delivery services at low latency under bursty traffic situations and in the presence of certain faults in either the network or processing elements. The R2 design is based on a damped adaptive routing scheme that avoids livelock, exhibits improved latency under bursty congestion, while performing similar to deterministic strategies in the lightly loaded case. This paper describes the R2 architecture and presents the results of a simulation study which motivates the damped adaptive routing strategy employed by the R2 switch. 3 1 Introduction The work presented here is a natural extension of previous work on a high performance router called the Post Office. The Post Office is a 300,000 transistor CMOS chip that is used to form the interconnect fabric for a prototype scalable parallel multiprocessing system called Mayfly [Davis92]. The Mayfly processing element (PE) architecture was designed..