Specifications
XBee®/XBee‐PRO®SERFModules
©2009DigiInternational,Inc. 48
AODV Mesh Routing
ZigBee employs mesh routing to establish a route between the source device and the destination.
Mesh routing allows data packets to traverse multiple nodes (hops) in a network to route data
from a source to a destination. Routers and coordinators can participate in establishing routes
between source and destination devices using a process called route discovery. The Route
discovery process is based on the AODV (Ad-hoc On-demand Distance Vector routing) protocol.
SampleTransmissionThroughaMeshNetwork
AODV (Ad-hoc On-demand Distance Vector) Routing Algorithm
Routing under the AODV protocol is accomplished using 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 not known, route discovery must take place in order to find a path. Since only a limited
number of routes can be stored on a Router, route discovery will take place more often on a large
network with communication between many different nodes.
When a source node must discover 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 is propagated through the network (refer to the Broadcast Transmission),
each node that re-broadcasts the message updates the path cost field and creates a temporary
entry in its route discovery table.
Node Destination Address Next Hop Address
R3
Router 6 Coordinator
C
Router 6 Router 5
R5
Router 6 Router 6