Optimized Link State Routing Protocol Using Detection lgorithm in Manet

Abstract

A mobile ad hoc network consists of mobile networks which create an underlying architecture for communication without the help of traditional fixed-position routers. Nevertheless, the architecture must maintain communication routes although the hosts are mobile and they have limited transmission range. There are different protocols for handling the routing in the mobile environment. This paper will focus on one well known algorithm: Optimized Link State Routing Protocol as well as shared cryptographic technique. Optimized Link State Protocol or OLSR is an optimization version of a pure link state protocol. So the topological changes cause the flooding of the topological information to all available hosts in the network. To reduce the possible overhead in the network, Optimized Link State Protocol or OLSR uses Multipoint Relays (MPR). The idea of MPR or Multipoint Relays is to decrease flooding of broadcasts by decreasing the same broadcast in some regions in the network. Another reduce is to provide the shortest path. The time interval reduction for the control messages transmission can bring more reactivity to the topological changes. (1, 3, 4, 5, 6, 7, 8) But before this, we need to prevent malicious hosts to enter into a particular zone. These malicious hosts are the victims of several attacks which are discussed later. Attack on a host leads to a malicious host, which interrupt the route in the communication path. Hence a trust based framework is essential to detect and recover from the network layer attacks like black hole attack, wormhole attack and Byzantine attack. Black hole attack interrupts the packets forwarding to the destination. Wormhole attack disrupts the routing and Byzantine attack degrades the routing services. To overcome these attacks the proposed trust based frame work calculates the observed trust value (OTV) and advertised trust value (ATV). The observed trust value refers to the route trust computed by the node itself based on the information in R_ACK and the advertise route trust is advertised by a downstream neighbor. Route selection value is calculated with the observed trust value and advertised trust value. Route selection value (RSV) is used as a metric in selecting one of the multiple paths available to a destination. The path selected by Route Selection Value is the trusted and the shortest path. Keyword: MANET, OLSR, Security, Attack, Trust