Deflection routing mechanism using BLESS and BBUS NoC

Abstract

Buffer is a very crucial component in giving performance of an Network on Chip (NoC). In short buffers governs the performance of an NoC. But the major problem with Buffers is that they are power hungry. In these paper two types of deflection Routers have been discussed. One is BLESS (Buffer less Router) where total ordering sorting circuits is followed by a sequential port allocation while in second one total ordering is replaced with Golden Flit Concept. BLESS NoC includes hot potato routing including free live lock. As compared to normal VC Routers we are eliminating three stage sorting circuit. Rather than going for sequential port allocation we are going for parallel port allocation called as permutation deflection logic. Golden Flit concept together with permutation deflection logic is responsible for reduction of 29% of Routers Critical Path. Also clock based synchronization in CHIPPER based NoCs increases latency. To avoid this issue BBus NoC (Broadcast bus NoC) concept is discussed. The worst case latency is reduced by using Golden Flit concept.