What you need to do is enable packet capture on switch port where 3905 is connected , compare SIP messages of both working and non working condition and see the SDP media ip and port in OK/ACK message of SIP.
Then look at network configuration , do you see any config which blocks that RTP port or Media IP ? and do some extended ping from SIP phone IP to remote media IP.
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...