| MANET (Mobile Ad hoc network) is made up of many wireless routers and can be easily deployed without the help of any existing network infrastructure. They are highly applicable for emergency deployments, disasters search and military operations. Due to infrastructure, self-organization, dynamic topology and openness of wireless links, ad hoc network routing protocols face more security problems than traditional network routing protocols that restrict the development of MANET. A powerful secure routing scheme plays an important role in the network. So, it is quiet necessary to design a strong security routing mechanism to prevent ad hoc network from numerous attacks.OLSR protocol is chosen as the researching object of the ad hoc routing protocol through analyzing and comparing. Security leak was found after the deep study of the OLSR routing algorithm, that OLSR has no security mechanisms, malicious nodes can perform many attacks, such as black hole attack, wormhole attack and sleep consumption attack .Wormhole attack model was specially described, and a convenient security solution was proposed to prevent the wormhole attack, which apply the simple wormhole detective mechanism and authentication to strength the neighbor relationship establishment, and extend the OLSR basic packet format, use hash-chain and digital signature to secure the routing packets unaltered by malicious nodes before received. At last, the solution about wormhole attack is extended to use exception monitor mechanism, can resist rushing attack and sleep consumption attack. It improves the security mechanism of OLSR protocol.NS is simulated software with open resource. The simulated environment it support including LAN, WLAN, IP network, MANET and satellite network. Currently, NS is used as mobile ad hoc network platform to simulate the improved routing protocol and execute performance analysis. It can not only analyze the performance of network efficiently, but also reduce the cost. |
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