A Novel Frame Forwarding Algorithm for Switched Networks

Abstract

Switched networks use meshed topologies for path redundancy; loop-free frame forwarding paths are established by protocols that use either the spanning or Dijkstra tree algorithms. When a network link or device fails, the tree must be repaired, leading to high convergence latencies impacting both broadcast and unicast traffic. Unicast frames are constrained to use the tree paths, which may not be the shortest path and links are not utilized uniformly. We propose a new meshed tree algorithm and meshed tree protocol (MTP) to provide non-looping paths (with backup) for broadcast frames. We also propose a new scheme for unicast frames to use shortest paths (provisioned with backup) between end devices. A novel virtual ID technique to construct the trees makes the protocol robust and provides fast failure recovery. In this article, we present implementation details of MTP on the GENI testbed and compare its performance with state-of-the-art loop-avoidance protocols.