1. Configuration Guide
  2. IMS Support
  3. ATCF INVITE ICSI Matching

ATCF INVITE ICSI Matching

The Oracle Communications Session Border Controller can check, on reception of an INVITE on an ingress sip-interface that has a configured ATCF and before applying any of the already implemented logic, whether the incoming INVITE includes the ICSI (Instantaneous Channel-State Information) of the requested service. The ATCF will be involved in the call flow when the configured ICSI value matches the ICSI value in the original INVITE; otherwise the handoff call will be rejected with code 480 (Temporarily Unavailable) or 404 (Not Found).

The system looks for the ICSI string in the following headers:

  • P-Preferred-Service
  • P-Asserted-Service
  • Feature-Caps (within the "g.3gpp.icsi-ref" feature-capability indicator)
  • Accept-Contact (within the tag-value within the g.3gpp.icsi-ref media feature tag)

An example of the ICSI string in the P-Preferred-Service or P-Asserted-Service header is "urn:urn-7:3gpp-service.ims.icsi.mmtel". Examples of the ICSI string in the Feature-Caps or Accept-Contact headers are "+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel" and "g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel". The ATCF will be involved in the call flow only when the ICSI matches. Configure the atcf-icsi-match parameter with the ICSI string you want to match. If atcf-icsi-match is blank, the check is not done and the behavior remains the same as before.