Ad-hoc On-demand Distance Vector routing (AODV) builds upon Destination-Sequenced Distance-Vector Routing (DSDV) which is a table-driven protocol based on the Bellman-Ford single-source shortest-path algorithm. DSDV maintains a routing table in every node. This table contains all the possible destination paths and the number of hops to each one. In contrast, AODV creates entries in a routing table on an on-demand basis and only nodes that participate in that path are contained in a node's routing table.

 When a source node needs to send a message to a destination node it initiates its path discovery process. This involves broadcasting a Route Request packet (RREQ) to the node's neighbors who then broadcast the RREQ to their neighbors. The RREQ will continue to be broadcast until it is received by the destination node or by an intermediate node with a routing table containing a path to the destination node.

 Contained in the RREQ are a broadcast ID, IP address, and most recent sequence number. The broadcast ID is maintained by every node and is incremented for every RREQ the node initiates. The initiating node's broadcast ID and IP address identify each RREQ. The sequence number is used to determine the freshness of the information contained in the RREQ. The destination sequence number is the greatest sequence number received in the past for any route to the destination node. The sequence numbers also help in keeping the protocol loop free.

 Upon receipt of the RREQ (by either the destination or intermediate node) the node will initiate a Route Reply packet (RREP). This packet will follow a reverse path back to the source node. As the RREP follows the reverse path, nodes along the path update their route table entries if the sequence number is
   (i) higher than the destination sequence number in the route table, or
   (ii) the sequence numbers are equal, but the hop count plus one , is smaller than the existing hop count, or
   (iii) the sequence number is unknown.

 Information contained in the routing table includes forward route entries to various destination nodes and a lifetime timer. The forward route entries are updated as an RREP follows its reverse path as explained above. Every time an entry is updated or used the lifetime timer will be reset for that entry. If the timer runs out that entry will be deleted on the assumpltion that that path is no longer needed or valid.

 AODV also implements a link failure notification message and a hello message. The link failure message is sent if a node notices that an intermediate node has moved and the hello message is a periodic local broadcast by a node to inform each node of the other mobile nodes in its vicinity.