Digi XBee 3 ZigBee User Manual page 105

Transmission, addressing, and routing
AODV routing algorithm
Routing under the AODV protocol uses tables in each node that store the next hop (intermediary node
between source and destination nodes) for a destination node. If a next hop is unknown, route
discovery takes place to find a path. Since only a limited number of routes can be stored on a router,
route discovery takes place more often on a large network with communication between many
different nodes.
Node Destination address
R3 Router 6
C Router 6
R5 Router 6
When a source node discovers a route to a destination node, it sends a broadcast route request
command. The route request command contains the source network address, the destination
network address and a path cost field (a metric for measuring route quality). As the route request
command propagates through the network (see
broadcasts the message updates the path cost field and creates a temporary entry in its route
discovery table.
The following graphic is a sample route request (broadcast) transmission where R3 is trying to
discover a route to R6:
Digi XBee® 3 Zigbee® RF Module
Next hop address
Coordinator
Router 5
Router 6
Broadcast transmissions), each node that re-
RF packet routing
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