Design And Analysis Of The High-Radix Router Switching Fabric

Advances in micro-electronics and signaling technology have enabled serialized transmission as an efficiently transmission mode. Using high-speed serialized-link will largely decrease router's pin number, and make the implementation of a high-radix router possible. Furthermore, statistics of typical high performance computers shows that the network radix increase significantly over time and using high-radix router is the trend of interconnection networks. Interconnection networks based on high-radix router only need several hops to joint thousands upon thousands processor nodes, thus reducing packet delays as well as the overall cost of a network.In this paper, we first analysis the various existing switching fabrics, summarizing their advantages and disadvantages. We then in-depth study a 64-port high-radix router named YARC. The switching theory, constitution fabric and arbitration procedure of YARC are all discussed. We point out that it is appropriate to use tile in the design of a high-radix router.The router's internal traffic under optimal routing in fat-tree network is also researched. Based on internal traffic, we then make a comparison on some port allocation policies of a 32-port switch chip. We proposed two improved switching fabric, both of which can make rows and columns uniformly distributed, making internal traffic balanced and improving switching performance.A high-radix switching chip named S32 is implemented. During the design of S32, a dual-port tile fabric and a logic-port based routing transform mechanism are proposed. We describe the switching fabric, pipeline design, routing transform mechanism, crossbar implementation ans so on detailedly. We construct an interconnection network based on S32 switching fabric. The simulation result demonstrates that our two proposed policies can achieve better performance, especially under communicaiton locality condition.