As HARIS_HUSSAIN  mentioned you could try a full reboot and see if that lines things backup but to be honest I've never had luck changing the ip/hostname of cucm servers even when following the guide.  Every time I've done it, I ended up having to open a TAC case and they needed to login as root and fix the host file and some other things.    The IP and hostname are referenced in many places and it doesn't seem to update them all correctly.  Most of the time for a subscriber I'll opt to blow it away and just rebuild it with the new IP.   ... View more

I don't think there is a way to do it on the router.  In my situation I have a MRGL with 2 different Resource Groups.  I switch the order of the MRGL in Call Manager making the router I want to upgrade lower in the list so its not picked first for calls.  This allows the calls to drain off.  You could also try removing the resource from the MRG, I don't think that will kill any active calls however if its the only transcoding resource in the group then future calls wont have it available if its needed.  However if the router is also rebooting from the upgrade it wouldn't be available for those future calls either so I guess that wouldn't matter.  Then after the upgrade put the list back to how they were and you should see it start taking calls again.   ... View more

Hi Enzo, It sounds like your RTP ports are being blocked by the firewall.  Once the call is connected the RTP audio stream uses UDP ports in the range 16384-32767. The first thing I would check is that this port range is open in the firewall.  HTH, James ... View more