20-07-2012, 02:37 PM
A Newly Routing Protocol for MANET
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Introduction
Mobile ad hoc network (MANET) is a collection of wireless mobile stations that collaborate to facilitate communications between themselves without invention of fixed wire/wireless infrastructure. The topology of the network changes dynamically as nodes move and the nodes reorganize themselves to enable communications with nodes beyond their immediate wireless communications range by relaying messages for one another [1].
DSR Protocol
DSR is an entirely on-demand ad hoc network routing protocol [6] composed of two parts: Route Discovery and Route Maintenance. In this section, we describe the basic form of Route Discovery and Route maintenance in DSR.
In DSR, when a node has a packet to send to some destination and does not currently have a route to that destination in its Route Cache, the node initiates Route Discovery to find a route; this node is known as the initiator of the Route Discovery, and the destination of the packet is known as the Discovery's target. The initiator transmits a Route Request (RREQ) packet as a local broadcast, specifying the target and a unique identifier from the initiator. Each node receiving the Route Request, if it has recently seen this request identifier from the initiator, discards the Request. Otherwise, it appends its own node address to a list in the Request and rebroadcasts the Request.
Security attacks in MANET
The main assumption of the ad hoc routing protocols is that all participating nodes do so in good faith and without maliciously disrupting the operation of the protocol [6, 7]. However, the existence of malicious entities cannot be disregarded in any system, especially in open ones like ad hoc networks. The RPSEC IETF working group has performed a threat analysis that is applicable to routing protocols employed in a wide range of application scenarios [8].
A Proposed Scheme
Our proposed scheme classifies the relationship among the nodes and their neighboring nodes in to three types as below. The relationship between any node x and node y will be determined according to the number of messages sent/received to/from y and it is given as follows:
Unknown (UK):
-Node x have never sent/received any messages to/from node y.
- Trust levels between them are very low.
- Probability of malicious behaviour is very high.
-Newly arrived nodes are grouped in to this category.
Simulation and Results
For the performance simulation of the protocol extensions, a regular well-behaved DSR network is used as a reference. We then introduce compromised stranger nodes into the network which doesn’t forward the packets. The network should identify these malicious nodes and not upgrade them to known nodes. Simulations are carried out for the forwarding defection of the nodes.