Meshed Tree Protocol for Faster Convergence in Switched Networks

Loop free forwarding is a continuing challenge in switched networks that require link and path redundancy. Solutions to overcome looping frames are addressed by special protocols at layer 2, which block ports in the bridges to build a logical spanning tree for frame forwarding. However, due to the continuing convergence issues in the Spanning Tree algorithm, IETF RFC 5556 Transparent Interconnection of Lots of Links on RBridges (router bridges) and IEEE 802.1aq Shortest Path Bridging both use link state routing techniques to build Dijkstra trees from every switch. Both techniques have the expense of higher processing complexity. In this paper, a novel meshed tree algorithm (MTA) is investigated to address convergence issues faced by STA while also avoiding the complexity of Link State routing. The MTA based protocol is compared with Rapid Spanning Tree Protocol using OPNET simulations. The significant reduction in convergence time combined with the simplicity in implementation indicates that the Meshed Tree Protocol would be superior candidate to resolve looping issues in switched networks.