Overview

The SBC Core can trace SIPRec legs to assist in debugging various issues associated with SIPRec legs, such as:

  • Missing media packets
  • Missing Signalling packets towards SIP Recording Server (SRS) in debug (.DBG) logs
  • Crank back issues in QUAD SIPREC

As part of the enhancement, the flag sipRecLegsCapture is introduced under the callFilter parameter of the global callTrace object.

When the main call is traced and SIPREC is invoked based on a matching criteria, if the flag sipRecLegsCapture is set to enabled:

  • For single and DUAL SIPRec calls:
    • The media packets of the main call's leg (non-SIPRec side) and the SIPRec legs are logged in .PKT file.
    • The .TRC file contains SIP Protocol Data Units (PDUs) for SIPRec calls, as well as tracing data of the main call (depending on the level of the trace).
  • For QUAD SIPRec calls:
    • Packets are not captured for the main call and the .PKT files do not have the media of the main call. However, media packets of the SIPRec legs are logged in the .PKT files.
    • The .TRC file contains SIP PDUs for SIPRec calls, as well as tracing data of the main call (depending on the level of the trace).

Behavior of sipRecLegsCapture based on Call Trace Filter Level

The effect of enabling the flag sipRecLegsCapture varies based on the level of the call trace filter, as described in the table below:

Behavior of sipRecLegsCapture based on Call Trace Filter Level

Call Trace Filter levelState of sipRecLegsCapture flagResult
Level 1/2/3enabled

If the main call is traced by the same call filter, the SBC captures SIPRec SIP PDUs in .TRC file and SIPRec legs Media in .PKT file.

Level 1/2/3disabled

The SBC captures neither SIP PDUs in .TRC file, nor media packets of the SIPRec legs in .PKT file.

Level 4enabled/disabled

SIP PDUs only for the specified peer IP are captured in .TRC file.

If the peer IP is same as the SRS IP, all SIP PDUs from and towards that SRS are captured.

If the peer IP is an end point, all SIP PDUs from and towards that end point are captured.

If the peer IP is 255.255.255.255, all SIP PDUs are captured.

Content of PKT file based on SIPRec Criteria and Number of Simultaneous Sessions

If call trace is triggered for filter level 1, 2, or 3, the information captured in .PKT file varies based on the SIPRec criteria and the number of simultaneous SIPRec sessions, as described in the table below:

Content of PKT file based on SIPRec Criteria and Number of Simultaneous Sessions

SIPRec Recording TypeNumber of simultaneous SIPRec sessions State of sipRecLegsCapture flagInformation captured in PKT file
All legs/Ingress1enabledEgress leg media packets of the main call, and media packets of SIPREC legs.
All legs/Ingress1disabledEgress leg media packets of the main call.
All legs/Ingress2 (DUAL SIPREC)enabledEgress leg media packets of the main call, and media packets of SIPREC legs.
All legs/Ingress2 (DUAL SIPREC)disabledEgress leg media packets of the main call.
All legs/Ingress4 (QUAD SIPREC)enabledMedia packets of only SIPREC legs.
All legs/Ingress4 (QUAD SIPREC)disabledNo media packets are captured.
Egress1enabledIngress leg media packets of the main call, and media packets of SIPREC legs.
Egress1disabledIngress leg media packets of the main call.
Egress2 (DUAL SIPREC)enabledIngress leg media packets of the main call, and media packets of SIPREC legs.
Egress2 (DUAL SIPREC)disabledIngress leg media packets of the main call.
Egress4 (QUAD SIPREC)enabledMedia packets of only SIPREC legs.
Egress4 (QUAD SIPREC)disabledNo media packets are captured.