I have been trying to find a document that describes the process the ip phones goes through to register to a Subscriber when the Publisher they are on is restarted manually.
From what I can make out, there is a controlled handover, causing minimal if any interuption. We have approximately 400 phones split across the Publisher and Subscriber. We have several teams working 24x7, so describing the impact accurately is important.
When I did the restart from the OS admin GUI on a vers 6.1.5, it didn't shutdown straight away. Can anyone tell me what is happening? Is the Publisher still operational but not sending out keepalive acknowledges allowing the phones to register to the Subscriber before it shuts down, or is there another handover process?
What interuption can be expected? What my customer observed was the phone indicator flashed. From what I have read connected calls are not dropped, calls not connected are, as are calls on hold.
We are currently in the transition of phones from the 6.1.5 system to a 8.6.1 system, does this later version use the same methodology?
Is the fallback from Subscriber to Publisher the same process or more controlled?
Peter
