Deterministic versus Adaptive Routing in Fat-Trees
|Research Area:||High Performance Clusters||Year:||2007|
|Type of Publication:||In Proceedings||Keywords:||PC clusters;adaptive routing;deterministic routing algorithm;fat-tree topology;interconnection networks;packet delivery;multistage interconnection networks;telecommunication network routing;telecommunication network topology;telecommunication traffic;tree|
|Book title:||Parallel and Distributed Processing Symposium, 2007. IPDPS 2007. IEEE International|
Clusters of PCs have become very popular to build high performance computers. These machines use commodity PCs linked by a high speed interconnect. Routing is one of the most important design issues of interconnection networks. Adaptive routing usually better balances network traffic, thus allowing the network to obtain a higher throughput. However, adaptive routing introduces out-of-order packet delivery, which is unacceptable for some applications. Concerning topology, most of the commercially available interconnects are based on fat-tree. Fat-trees offer a rich connectivity among nodes, making possible to obtain paths between all source-destination pairs that do not share any link. We exploit this idea to propose a deterministic routing algorithm for fat-trees, comparing it with adaptive routing in several workloads. The results show that deterministic routing can achieve a similar, and in some scenarios higher, level of performance than adaptive routing, while providing in-order packet delivery.