AVR2070
33
8240B-AVR-06/09
Figure A-4-2 Direct Association Message Sequence
End/Router Node Pan Coord Node
Association Request
Association Response
The node then associates to its parent as illustrated in figure A-4-2 (above):
The node sends an Association Request packet to the chosen router (or coordinator).
The association request payload includes the MAC address of the end node, the
short address of the parent router node, and the type of the requesting node (router
or end). This request is forwarded to the coordinator, and the coordinator issues a
response, which is routed back to the new node.
The node receives an Association Response packet from the router (originating from
the coordinator). The newly associated node then stores the two short addresses
contained in the association response – its own short address and parent's short
address.
When the node becomes associated, it must only store a few bits of information to be
connected to the network.
• Its own short address (16 bits).
• The short address of its parent (16 bits).
• The PAN ID of the network (16 bits).
• The channel of the network (8 bits).
The node sends data to coordinator periodically per the application, via the parent
router (or coordinator if the node is directly connected to the coordinator).
A.4.2 Router node
The router node can act as an intermediary between end nodes and the rest of the
network. It can either be directly associated with the coordinator, or indirectly through
a chain of router nodes. The direct scenario has been illustrated in figures A-4-1 and
A-4-2 and the indirect scenario is illustrated in figure A-4-3. A router node can also
perform the duties of an end node, sending data readings as the application requires.