VoIP Trace is a Cisco Unified Border Element (CUBE) serviceability framework, which provides a binary trace facility for troubleshooting SIP call issues. The VoIP Trace framework records both successful and failed calls. All call trace data is stored in system memory. In addition to being stored in the system memory, data for calls with IEC errors is also written to the logging buffer.

The VoIP Trace feature is enabled by default and may be used to help troubleshoot issues, even in deployments with high call volumes.

router (config)#voice service voip
router(conf-voi-serv)#trace
router(conf-serv-trace)#?
Voip Trace submode commands:
default Set a command to its defaults
exit Exit from voice service voip trace mode
no Negate a command or set its defaults
shutdown Shut Voip Trace debugging
memory-limit Set limit based on memory used

Within the VoIP Trace sub-mode (conf-serv-trace), you can configure the following CLI commands:

• memory-limit [platform | memory]

• no [shutdown]

VoIP Trace is used for event logging and debugging of VoIP parameters. Using the VoIP Trace framework, the following information is recorded:

• SIP messages for SIP trunk to SIP trunk calls

• CCSIP messages, Events, and APIs for CUBE

• SIP Errors

• Call Control (Unified Communication flows processed by CUBE)

• FSM (Finite State Machine) states and events

VoIP Trace monitors and logs SIP signalling and call events in memory as they occur. In the event that a call error is detected, or calls fail with 3xx, 4xx or 5xx cause codes, these event details are written to the logging buffer after the call clears.

Note	Traces for error calls are logged at the rate of up to five traces per second.

There’s a configurable memory limit allocated for storage of traces in a VoIP Trace framework for CUBE. The maximum memory limit that you can configure for VoIP Trace is 1000 MB. By default, VoIP Trace will use up to 10% of the available platform memory. For example, if CUBE is used on a platform with 8GB of RAM, VoIP Trace will use up to 800MB for trace data. Once the trace memory limit is reached, older traces are overwritten and will no longer be available.

Router(conf-serv-trace)#memory-limit ?
  <10-1000>  Specify maximum memory limit in MB
  platform   Use 10 percent of available memory

To display the traces for a call, use the following show command:

• show voip trace {call-id identifier | session-id identifier | sip-call-id identifier | correlator identifier | all | cover-buffers | statistics | detail }

Cisco IOS XE Amsterdam 17.3.2, Cisco IOS XE Bengaluru 17.4.1a or a later release supported by CUBE.

• Unable to trace incoming calls if active calls exhaust the memory-limit.

• It is not possible to trace calls with a single SIP leg using the trace command.

The following are some of the benefits of VoIP Trace Serviceability framework:

• Enabled by default

• Minimal CLI configuration requirement

• Minimal processing impact

• Automatic call error identification and trace logging based on IEC Errors

• Request-based manual call error identification and trace logging (filtered by call-ID, session-ID and so on)

The following are some of the usage guidelines for the VoIP trace Serviceability framework.

• Enable or disable your VoIP trace serviceability framework using the following CLI commands:

  • Enable—Configure trace under voice service voip configuration mode to enable your VoIP trace framework (trace is enabled by default).

  • Disable—Configure shutdown under voip trace configuration mode to disable your VoIP trace framework. To enable VoIP trace after it’s disabled, configure the CLI command no shutdown .

• If you configure shutdown the VoIP trace serviceability framework:

  • Stops tracing for active calls.

  • Deletes all existing traces in the system memory.

• Monitors calls received after enabling VoIP trace.

• Traces stored in memory can be displayed using the show command show voip trace {call-id identifier | session-id identifier | sip-call-id identifier | correlator identifier | all | cover-buffers | statistics [detail] }

  • The show command displays traces for both active and disconnected calls.

  • The show command displays information only for the SIP leg.

  • For media forking, VoIP trace also displays information for forked legs.

  • Voice trace can be filtered by tenant tag.

• For the CLI command memory-limit [platform | memory ]

  • Configure memory-limit platform to set 10% of the total memory available to the IOS processor at the time of configuring the command as VoIP trace memory limit.

  • Configure memory-limit memory to set a custom VoIP trace memory limit. Range is 10–1000 MB.

    • Configuration of custom memory-limit more than the available platform memory is not allowed. Configuration fails with an error message:

      
      router(config)#voice service voip 
      router(conf-voi-serv)#trace
      router(conf-serv-trace)#memory-limit 800
      Error: Setting memory-limit more than available platform memory (732 MB) is not allowed.
      

    • Configuration of memory-limit more than the 10% of the available platform memory affects the system performance. Configuration is successful with a warning message:

      
      router(config)#voice service voip 
      router(conf-voi-serv)#trace
      router(conf-serv-trace)#memory-limit 100
      Warning: Setting memory limit more than 10% of available platform memory (73 MB) will affect system performance.

  • Reducing the memory-limit from an existing limit resets the VoIP trace data. Take copy of the show voip trace statistics detail and show voip trace all output data before reducing the memory-limit.

    • A confirmation message is displayed when you reduce the memory-limit from an existing limit:

      Reducing the memory-limit clears all VoIP Trace statistics and data.
      If you wish to copy this data first, enter ‘no’ to cancel, 
      otherwise enter ‘yes’ to proceed.

  • Increasing the memory-limit does not impact the VoIP trace data.

  Note

  VoIP trace is unable to trace incoming calls if active calls exhaust the memory-limit. To change the Timestamps displayed in the VoIP trace, configure the following: router(config)#monitor event-trace timestamps datetime ? localtime Use local time zone for timestamps msec Include milliseconds in timestamp show-timezone Add time zone information to timestamp

A syslog message is generated in the following format, when CUBE is configured to register with a SIP trunk:

SIP Trunk Registration Success

*Aug 12 08:50:41.922: %SIP-3-REG_INTERNAL: Registration Success. Tenant=300;Number=slido123;registrar=dns:slido.com;addr=8.0.0.121;port=6123;connid=4

SIP Trunk Registration Failure

*Aug 12 08:50:41.876: %SIP-3-REG_INTERNAL: Registration failed. Tenant=200;Number=Engineering2541_LGU;registrar=dns:xyz.cisco.com;addr=8.0.0.121;port=9072;connid=3

Note	The syslog message is logged whenever there is change in registration status (from success to failure and vice-versa). If there are consecutive successful or failure responses, only the first successful or failure response is logged.