1. Configuration Guide
  2. IMS Support
  3. SRVCC PS-CS Access Transfer
  4. SIP Feature Capabilities

SIP Feature Capabilities

The ATCF can announce a feature capability in a message by transporting the information in the Feature-Caps header, which is supported by the SBC.

The behavior of the two anchoring points, ATCF and ATGW, is defined by 3GPP in Release 12 of Technical Specification TS 24.237. Oracle Communications developed these functional entities based on the initial version of TS 24.237 Release 10, and has added the sip-feature-caps configuration element to align with Release 12.

When the state is enabled, the SBC includes the Feature-Caps header in applicable SIP messages. The information in the header is dependent on sip-feature-caps configuration.

Specifically, When you enable sip-feature-caps, regardless of other settings, the SBC inserts the Feature-Caps header with:
  • The g.3gpp.mid-call capability indicator.
  • The g.3gpp.atcf-path parameter with a value set to the ATCF URI for terminating requests
Assume the state is enabled and both atcf-alerting pre-atcf-alerting are disabled. The SBC adds the Feature-Caps header with the above and:
  • The g.3gpp.atcf parameter with a value of the configured atcf-stn-sr in sip-config
  • The g.3gpp.atcf-mgmt-uri parameter with a value of the configured atcf-psi-dn in sip-config

Finally, when state is enabled, atcf-management-uri is not disabled, and atcf-alerting is enabled, the SBC adds the Feature-Caps header with the above and also adds the g.3gpp.srvcc-alerting capability indicator. Similarly, the SBC adds the g.3gpp.srvcc-pre-alerting capability indicator when atcf-pre-alerting is enabled.