Wbridge Routing with Minimal Control Messages in Multi-Hop Wireless Ad-Hoc Networks

Existing wireless ad hoc routing protocols, such as DSDV, AODV, DSR, TORA and GPSR, rely heavily upon the use of a large number of control messages to build and maintain routes between communicating mobile end-points. In this thesis, we present the design and evaluation of WBridge -- an ad hoc wireless routing protocol that greatly reduces the number of control messages required to discover and maintain routes. The WBridge protocol operates in a manner similar to the transparent bridges in the traditional wired LAN environments. Like wired bridges, WBridges observe packets in transit and apply backward learning mechanism to transparently learn forwarding paths to the destination. Unlike wired bridges, however, WBridges do not need to construct or maintain extensive network-wide spanning trees. Furthermore, it can be proved that transient routing loops do not last longer than a bounded time period. The WBridge protocol requires no control messages to construct and maintain routes for bidirectional traffic (such as TCP connections) and minimal data-like control messages for one-way traffic (such as streaming UDP). Additional advantages of WBridge protocol include low-latency route setup, network throughput comparable to state-of-the-art routing protocols, no need for promiscuous-mode operation of wireless interface and elimination of ARP request/reply messages.