Digimesh Node joining procedure

Scenario A is:
Existing established digimesh network with aggregator node.
A new node joins the network with DH/DL set to zero.
All other settings are the same for all nodes.
How does the new node make itself known to the aggregator so DH/DL for the new node are set to the correct values?

Scenario B is:
Existing established digimesh network node with a primary aggregator node.
A second node is designated as the standby aggregator node for redundancy. The secondary node is a passive listener while the primary node is functional
The primary aggregator fails.
What fail-over procedure should the secondary aggregator node use to find out that the primary aggregator node has failed?

Which XBee products are you referring to? Please note that there are different Digi Mesh protocols as it has evolved over the years so it is very important to indicate which module and firmware version you are referencing.

I have figured out that if I always give an aggregator the same name eg. “server”, then I can do a Network discovery (ND) command to find the “server”, or a Discover Node (DN) command, I can identify the aggregator. I can then load the DL, DH values with the aggregator MAC address.

For the second scenario, I can implement a watchdog timer on the secondary aggregator that pings the primary one. If the watchdog times out, the secondary can issue a AG command to have all members of the network send through the new primary.