Aodv Protocol Local Repair And Multi-path Routing

Mobile Ad Hoc Networks is a distributed-control and multihops network without specific fixed conmunication facilities. Since the advantages of independence of fixed-facilities and roubust scablility, it is widely adopted both in military and civil affairs. Because the nodes share the wirless channel, the network topology changes rapidly and the link-layer is not security enough, Ad Hoc network face many challenges.This dissertation focus on the link failure problem due to the rapid change of topology, try to find a method to recover the failed route quickly which could decrease the propobility of data packets loss. This dissertation bases on the AODV protocol, propose two new protocol: AODVNB (AODV Neighbor-Based protocol) and AMPLR (AODV Mulit-Paths with Local Repair).AODVNB taking the advantages of passive local repair and backup local repair, bring out a new mixed repair-mechanism. In small area, it takes back-up route to rapid repair; when back-up repair fail, it employ the TTL-extention mechanism to decrease the delay of route rebuild. Precusors repair has also been introduced in this algrithm to enhangce this protocal. The intra-area back-up repair solve the reliability problem of present protocol, it also void the delay of the route request and repley, realize the rapid route repair. The extra-area repair extend the TTL of RREQ according to the neighbores information, control the overhead and decrease the delay of the repair to destination.AMPLR is a new node-disjoint mulitpath protocal. It solve the problem in the routig discover phase and maitain phase in AODVM inspectively, improve the capability of the multi-paths discovery and maintence. There is another local repair algrithm is inclueded in AMPLR according to the multipath-routing characteristics. The repaird route can be used as backup route, to decrease the frequency of route discovery; it also can use the repaired route to forward the data packets, so it decrease the propobility of data packets loss. This paper has realized the simulation of AODVNB and AMPLR on OPNET system simulation platform.Under different network environments, with the comparison of the performance of the traditional AODV protocal and related researches, the simulation result verify the performance improvement of these two protocols.