Exploiting Parallelism to Boost Data-Path Rate in High-Speed IP/MPLS Networking

Link bundling is a way to increase routing scalability whenever a pair of Label Switching Routers in MPLS are connected by multiple parallel links. However, link bundling can be inefficient as a Label Switched Path (LSP) has to be associated with a particular link. In this paper, we show that the efficiency of link bundling can be significantly improved if traffic can be effectively distributed across the parallel links. We propose an IP switch architecture that is capable of distributing flows both inside the switch and among the parallel links based on operations that are relatively simple to implement. The switch requires no speedup, guarantees in-sequence packet delivery for a given flow, avoids complex co-ordination algorithms, and can achieve LSP throughput higher than the line rate. By means of simulation using IP traces, we investigate the performance of the proposed switch, and show that the switch achieves good load-balancing performance. We describe extensions to the basic architecture which allows for very large bundle size, handles incremental upgrade strategy, improves reliability, and accommodates non-IP traffic. Keywords— Switch architecture, link bundling, hashing, load balancing, performance.