Secure self-healing network


I am trying to create a secure self-healing network using XBee modules (S2B). My current setup includes a coordinator, 3-4 router with full topology interconnection between them and the coordinator & 3 end nodes.
End nodes are programmed to sleep for long intervals. For security purposes, the NJ parameter is set to 0 and EE=1 to keep external devices from joining the network.

Initially, I create the network by setting long NJ times and after all nodes have joined, all NJ parameters are set to 0.

In the X-CTU UI, end-nodes appear to be associated to a single router. If this router fails (power down) they are incapable to (re)join another router, even though all routers are in range (< 3-4 meters).

Is this standard zigbee operation? Is there a way to enable association of end-nodes to multiple routers? I would assume that orphan end nodes that already belong to the network (and know the link key) can connect to another router and keep communications alive, if their parent router is unavailable.

You can’t have an End device associated to more than one router at any given time. This would cause confusion on the network and prevent data from being received. Now if you set your NJ values to say 0x10, then the network will only allow joining for a short time frame. This should also then allow end devices that have become orphaned, to rejoin while keeping undesired nodes from Joining.