This document serves as a hub for data needed when troubleshooting Cisco IP Phone issues with phones that are registering to Cisco Unified Communications Manager (CUCM).
It is important to understand the phone registration process.
show risdb query phone
If the phone shows registered on RIS DC and shows unregistered on the GUI then there is an issue between RIS DC and the GUI.
Note: For SIP phones be sure to look at the expires field in the SIP register message found in the pcap. The default value for this field when the message is sent from the phone to it's primary CCM is 120 seconds. When the phone is sending a "keep alive" register message to it's secondary CCM server the expires field is 0.
Tip: The things below will require web access to be enabled on the phone and you may need to enable certain debugs. Even if a phone isn't registering you can sometimes change the settings on the phone. It is worth trying to enable webaccess, span to pc port,and SSH Access. If the issue is CTL or ITL related you will not be able to change the settings on the phone.
If 802.1x is in use, gather the output from the following commands:
Replace $if_name$ with the name of the interface (i.e. FastEthernet0/1)
The output of show itl and show ctl from all TFTP servers in the CUCM cluster
Determine if the cluster is in mixed-mode:
run sql select paramname,paramvalue from processconfig where paramname='ClusterSecurityMode'
Determine if the rollback parameter is set to true:
run sql select paramname,paramvalue from processconfig where paramname='RollBackToPreGrayback'
Determine if database replication is healthy:
utils dbreplication runtimestate
Note: If the cluster is not in mixed-mode, the output will look like this:
admin:run sql select paramname,paramvalue from processconfig where paramname='ClusterSecurityMode'
Note: If the rollback parameter is set to false, the output will look like this:
admin:run sql select paramname,paramvalue from processconfig where paramname='RollBackToPreGrayback'
Tip: For an explanation of the output from utils dbreplication runtimestate review this document.
These documents are great resources for understanding and troubleshooting phone VPN issues.
An important thing to note is the you can install an LSC on a phone without being in mixed mode (without a CTL file). This is because of the ITL. The only reason to use mixed-mode in CUCM version 8 and higher is to do encrypted signaling/media.