Design and investigation of scalable multicast recursive protocols for wired and wireless ad hoc networks

D

(b) Sending the route reply message backward to the source

Figure 2.3 The Route Discovery implemented at AODV [16].

2.4.3.2 Dynamic Source Routing Protocol (DSR)

DSR [43] is a reactive ad hoc routing protocol based on the source routing concepts. Each
node maintains a route cache to keep previously known routes to this node, where the
information kept in each node will expire if it is not used for a predefined period of time.

When a node needs to send data to a destination, it searches in its cache for a route to that
destination, if the route exists, then the node starts sending data to that destination.
Otherwise, a route request message as part of route discovery procedure will be created and
propagated in the network. The intermediate node upon receiving the route request message
searches in its cache for a route to this destination. If the route to the destination not found, it
appends its address to the route request message and propagates the message to its
neighbours.

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