Query-Localized Route Repair Mechanism for Ad-hoc On-demand Distance Vector Routing Algorithm

Abstract

Ad-hoc networking is a concept in computer communications, which allows applications to communicate with each other by forming a temporary network, without any form of centralized administration. With the increasing popularity of mobile ad-hoc networking, the need to connect large numbers of wireless devices is becoming more prevalent. Each node participating in the network has both communication and computation capabilities and acts both as host and a router. The proliferation of such mobile devices in recent years has in turn given a boost to the amount of attention to mobile ad hoc networks (MANET) due to their potential applications. On-demand routing is an important aspect of the current ad-hoc networking protocols, in which a route between a communicating node pair is discovered only on demand. However, links of MANETs are dynamic in the sense that they often experience breakage and changes as they move in the network, and link breakages severely deteriorate network throughput and routing performance. Existing ad-hoc routing schemes such as AODV propose end-to-end route repair schemes which often entail additional route maintenance overhead with little or no improvement in network performance. We propose a more reasonable route error handling scheme in keeping network performance goals. We call it Query Localized Route Repair (QLRR) where in the upstream neighbor that discovers the link failure tries to recover the route locally by discovering a route to the destination with itself as the source. While doing so the upstream nodes tries to limit the flooding to the nodes that are located in the vicinity of the original route. In this work we have incorporated our routing handling strategy into AODV’s route maintenance scheme for our study. Our strategy is able to recover from link failures based on local interactions instead of performing a global route re-discovery. To demonstrate the effectiveness of our approach we compare our scheme with the default route error mechanism of AODV. For evaluating our approach in terms of reliability, the average delivery ratio was measured. To estimate the network routing overhead the number of protocol packets, and application packets transmitted were measured. Results show that QLRR makes a substantial improvement in the protocol routing overhead which is crucial for scalability of ad-hoc networks while the delivery ratio is also improved.