Wireless ad-hoc networks are composed of autonomous nodes that are self- managed without any infrastructure. In this way, ad-hoc networks have a dynamic topology such that nodes can easily join or leave the network at any time. Ad-hoc networks are suitable for areas where it is not possible to set up a fixed infrastructure. Since the nodes communicate with each other without an infrastructure, they provide the connectivity by forwarding packets over themselves. To support this connectivity, nodes use some routing protocols such as AODV, DSR and DSDV.
We select AODV protocol because, AODV is capable of both unicast and multicast routing. It is a reactive routing protocol. AODV avoids the counting to infinity problem of other distance-vector protocols. AODV protocol is a flat routing protocol it does not need any central administrative system to handle the routing process.
Distributed Denial of Service (DDoS) attacks involve breaking in to hundreds or thousands of machines, so for this reason, this attack called Distributed. This kind of attack, consume more bandwidth and uses more sources in network. One of the most important attacks of DDoS attacks category is Black hole attack.
A black hole attack is a severe attack that can be easily employed against routing in mobile ad hoc networks. A black hole is a malicious node that falsely replies for any route requests without having active route to specified destination and drops all the receiving packets. If these malicious nodes work together as a group then the damage will be very serious.
Once the RREQ reaches the destination or an intermediate node with a fresh enough route, the destination or intermediate node responds by unicasting a route reply (RREP) packet (Figure 2) back to the neighbor from which it first received the RREQ.
Caused Of Black Hole Attack (Cont..) Fig2: The path of a route reply
The performance of routing protocols AODV depends heavily on much kind of attacks. One of these attacks is Black hole attack. This attack has high effect on AODV protocol. I want to show the performance of AODV protocol when it is effected by the black hole attack. I use network simulator-2(NS-2) to show the performance of AODV protocol during black hole attack.