Route discovery in AODV 

Whenever a node needs to communicate with other nodes across the network, it configures few parameters and attributes as discussed. First step followed in this case is that, the source node check its routing table to find an entry with the destination IP address and if it could find the same, simply it used the routing information from the table and closes the communication process. If the source node could not find any entry in its routing table it follows the below sequence of steps to proceed with the communication. 

  • RREQ message is created with few attributes like hop count to destination, source IP address, destination IP address, sequence numbers of source and destination and a unique broadcast ID
  • Source node broadcasts the RREQ message and waits for some time by counting the time with a timer
  • Now all the nodes which receive the RREQ message, check the message ID and compares with the existing messages and if they could find that, this message is already processed, they simply discard the message
  • If any receiver find that this message is unprocessed, it checks the destination IP address and compare with the routing information of their own tables. If the receiver is the destination, message is processed and if the receiver has a available route to the destination IP address, it simply forwards the message towards the route it has in the table.
  • Whenever the receiver processes the RREQ message it replies to the source in form of a Unicast message RREP. Now the source maintains the IP address of the nodes which delivered this message for the further usage.

This paper is written and submitted by Sujana Priya V.