I'm trying to better understand how RTMT works with regards to device search and in particular a device search for unregistered phones. We have a particular branch office that seems to be having connectivity issues, but our networking team is having trouble even confirming it's happening. We've been relying on RTMT to see the branch office phones unregister in order to alert the networking team what time we see issues happening. However, this past week an event happened that has made us question the validity of what we're seeing because we apparently don't understand how the tool works.
This past week our main office experienced a power outage and the phones on a particular PoE switch went down because that switch is not on a UPS. So we went into RTMT a couple of hours afterward to look at the list of unregistered phones from that power outage. We did not see any of the phones listed that we were expecting. It's as if they never unregistered.
So thinking it works on some type of polling interval, I powered off a phone for 5 minutes and then checked RTMT. I did see that phone in there. However, as soon as it was plugged back in, it was no longer listed in the unregistered phones after a device search. That makes some sense, but doesn't make complete sense why some phones are always listed in the unregistered phone device search. Even while listed in the unregistered phone device search they are currently registered with CUCM. I would expect RTMT to maintain a list of phones that have unregistered for a certain length of time for historical search purposes. It appears to be doing that, but also not doing that.
Based on all of that, it appears I do not understand how the whole mechanism for how phones appear in the unregistered device search. Anybody that can enlighten me to how this all works?
