Atmel AVR2070 User Manual

 

8240B-AVR-06/09 

8.  Some pre-deployment configuration can be used to determine whether a 

given node should or can join a given network.  This configuration is part of 
the application, not the MAC. 

9.  Only short (16-bit) 802.15.4 addresses are used in sending data over the 

network except during association, since a new node does not have a short 
address until it is issued one. 

10.  The coordinator's short address is defined to be 0x0000. 

The message sequence chart in Figure A-4-1  shows the effect of the end node 
“scanning” a particular channel by sending out a beacon request and receiving a 
beacon. 

End/Router Node

Pan Coord/Router Node

Beacon Request

Beacon

 

When the end node powers up, it performs a scan to find a parent node. 

The node sends a beacon request frame on each channel and listens for beacon 
frames.  The node picks a router based on the following criteria: 

1.  Pick the router/coordinator with the highest LQI value for the link. 

2.  In event of a tie with LQI, pick the router/coordinator with the lowest number 

of hops to a coordinator. 

3.  In event of a tie with hops, pick the highest RSSI value for the link. 

 
Note: 
If the compile flag DEMO is set, these criteria above are altered to only 
find the best RSSI during association. This provides a mechanism to 
demonstrate multi-hop routing.