I have seen this before. This only seems to happen when the phones are registered with a Callmanager which is across the WAN. What is your topology? Does this happen when all Callmanager servers and ip phones are on the same LAN?
Sniffing the network would help to see if there is any connectivity issues. As this is intermittent, it is really hard to track down.
SIP traces provide key information in troubleshooting SIP Trunks, SIP
endpoints and other SIP related issues. Even though these traces are in
clear text, these texts can be gibberish unless you understand fully
what they mean. This document attempts to br...
Please find the attached HTML document, download and open it on your PC.
This provides an easy to use form where you simply answer a few
questions and it will render the proper jabber-config.xml file for you
to copy/paste. There is built in logic to verif...
CUCM Database Replication is an area in which Cisco customers and
partners have asked for more in-depth training in being able to properly
assess a replication problem and potentially resolve an issue without
involving TAC. This document discusses the bas...