fallback-dn

[speakeasy51]

Can someone point me to a Cisco doc which can provide info on this command ?

[mhanderson]

Mee to. My customer is asking me and I don't have a clue. Some of the Cisco documentation shows the command in configurations for FXS stcapp supplementary-services but no description is provided.

[Bill Cameron]

From what I understand, fallback-dn is pulled from UCM via sccp. 
For example:

1. from UCM configure an analog port for vg202 port 0/0 with DN "12345"

2. once the vg202 registers with UCM, it will pull this information via sccp

3. fallback-dn will autopopulate as "12345" in running config.

[Pankaj_yadav]

What if port is not getting registered with cucm