Research On Fast Repair Mechanism Of Link In HWMP

Compared to single protocol,the Hybrid Wireless Mesh Protocol(HWMP)is a hybrid routing protocol,which means it can better meet the needs of different scenarios on the agreement,therefore,the importance of Mesh network gradually emerged.The time-varying nature of the underlying wireless link in Mesh network makes the link between Mesh nodes frequently disconnected and presents a great challenge to the normal communication between nodes.This also increases the frequency of path discovery,the end-to-end delay and the load in the network.So,in order to solve the above problems of HWMP protocol,some different improvement methods will be proposed in the dissertation which are used in proactive routing mode and on-demand routing mode respectively:(1)The forwarding information of Proactive tree building mode will be created/updated by using the Proactive PREQ mechanism or the Proactive RANN mechanism.When a Mesh node detects a broken link towards the root Mesh node,it can be repaired by FRHWMP under the fast repair mechanism proposed in this paper,that is,before sending PERR,first through a small part of the way to repair the broken link,so as to shorten the repair delay,take as little bandwidth as possible to repair the broken link.(2)In the RM-AODV(on-demand)routing mode,in order to improve the robustness of wireless Mesh networks and effectively solve the problem caused by broken link,multi-path HWMP protocol based on the related protocols of routing layer was proposed,that is AMHWMP protocol,our objective is to compute multiple disjoint loop-free paths in a path discovery,if some path was broken,the path was immediately replaced by the backup alternative path.Thus,this will not only avoid the reconstruct discovery,improve the reliability of the Mesh network,but also indirectly completed the repairment of broken link.In addition,the FRHWMP protocol and the AMHWMP protocol are simulated under NS3,and the performance of the end-to-end delay and packet delivery rate is compared and analyzed.The simulation results show that,AMHWMP packet delivery rate performance increased by about 10%,the delay performance increased by about 27%,while the FRHWMP protocol packet delivery rate performance is increased by about 9%,the delay performance increased by about 12%,compared with HWMP.Therefore,AMHWMP and FRHWMP protocol is more suitable than default protocol to meet the needs of different scenarios.