Otherwise, the node will reverse the route based on the route record in the Route Request message header (this requires that all links are symmetric).
In the event of fatal transmission, the Route Maintenance Phase is initiated whereby the Route Error packets are generated at a node.
The connection setup delay is higher than in table-driven protocols.
To avoid using source routing, DSR optionally defines a flow id option that allows packets to be forwarded on a hop-by-hop basis.
This protocol is truly based on source routing whereby all the routing information is maintained (continually updated) at mobile nodes.
This route cache is also used during the route construction phase.
This protocol uses a reactive approach which eliminates the need to periodically flood the network with table update messages which are required in a table-driven approach.
Each node, upon receiving a Route Request packet, rebroadcasts the packet to its neighbors if it has not forwarded it already, provided that the node is not the destination node and that the packet’s time to live (TTL) counter has not been exceeded.
Each Route Request carries a sequence number generated by the source node and the path it has traversed.In a reactive (on-demand) approach such as this, a route is established only when it is required and hence the need to find routes to all other nodes in the network as required by the table-driven approach is eliminated.The intermediate nodes also utilize the route cache information efficiently to reduce the control overhead.To return the Route Reply, the destination node must have a route to the source node.If the route is in the Destination Node's route cache, the route would be used.The accumulated path information is cached by nodes processing the route discovery packets. To accomplish source routing, the routed packets contain the address of each device the packet will traverse.