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Setting up UC500 for debugging SIP Trunk issues


This tech tip goes over what logs to gather when running into an issue with the SIP trunk on the UC500 that  relates to

  • inbound or outbound calls failing
  • SIP  registration failing
  • DTMF digits cannot be entered

NOTE: Ensure you note the time of the call, calling & called numbers  & any other relevant information if there are multiple calls in the log

1. Basic debug logs:

The first step is to gather basic logs with CCA 2.1 or higher

  • UC500 Configuration - On CCA, go  to Troubleshoot > IOS Exec Commands and choose “show running-config” in the  field for Command, then click Run and paste the output into a text file


  • UC500 Version  - On CCA, go to Troubleshoot > IOS Exec Commands and enter “show  version” in the field for Command, then click Run and paste the output  into a text file


  • VoIP Debug logs - On CCA, go to Troubleshoot >  Telephony Diagnostics > Voice Debug Log. Select device, check VoIP  (SIP) & Dial Plan and click Apply Debug. Make the failed call or the event, save log file to Log File Directory and click on Generate Troubleshooting Log.  Then click OK to disable debug logging.


2. Advanced debug logs

These are logs that are required in addition to the ones above. This are more verbose and should be run only when there is limited traffic through the UC500. Most times, a TAC engineer may request these.

  • Enable the below debugs by going to Troubleshoot > Generic debugs and entering the below on the "Debug Command List" window. Follow the steps on the screen to gather logs.

NOTE: CCA 2.2.2 or higher should be used for this option

debug ccsip message

debug voip ccapi inout

debug voip dialpeer inout

debug voice translation

debug voice source-group

debug voip rtp session named-events


3. Gathering Wireshark traces

This option is relevant if the issue is more related to the audio stream (RTP) or if there are additional devices such as firewalls in front of the UC500 or to document proof for the SIP trunk service provider who may not be able to read the UC500 debug logs. Steps to gather the wireshark trace include:

  • Setup a PC with wireshark capture from
  • Connect a HUB or SWITCH on the WAN Interface of UC500. Connect the PC to the same HUB or SWITCH to ensure all traffic going in & out of the WAN traffic can be captured by the PC


  • Enable Wireshark capture on the PC with a filter set up for SIP & RTP traffic to / from the UC500 - example is below


  • Make the failed call or event
  • Stop the capture and save the trace file. Be sure to note the IP address of the UC500 WAN port and the SIP trunk service provider's SIP proxy IP address