C.28 Definition of feature-capability indicator g.3gpp.dynamic-e-stn-drvcc

24.2373GPPIP Multimedia (IM) Core Network (CN) subsystem IP Multimedia Subsystem (IMS) service continuityRelease 17Stage 3TS

Feature-capability indicator name: g.3gpp.dynamic-e-stn-drvcc

Summary of the feature indicated by this feature-capability indicator:

This feature-capability indicator, when included in a Feature-Caps header field as specified in IETF RFC 6809 [60] in a SIP response to a SIP INVITE request, indicates support to transfer the session to the circuit switched (CS) domain using the Emergency Session Transfer Number for DRVCC digit string.

Feature-capability indicator specification reference:

3GPP TS 24.237, http://www.3gpp.org/ftp/Specs/archive/24_series/24.237/

Values appropriate for use with this feature-capability indicator:

String with an equality relationship. When used in a Feature-Caps header field in a SIP response, the value is string containing the digit string in tel URI format of the Emergency Session Transfer Number for DRVCC to be used to establish a CS call in order to transfer the session to the CS domain following the syntax as described in table C.28-1 for g-3gpp-dynamic- e-stn-drvcc.

Table C.28-1: ABNF syntax of values of the g.3gpp. dynamic-e-stn-drvcc feature-capability indicator

g-3gpp-dynamic-e-stn-drvcc = TEL-URI

TEL-URI = "<tel:" global-number-digits ">" ; global-number-digits as specified in IETF RFC 3966[79]

The feature-capability indicator is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: This feature-capability indicator is used to indicate support to transfer the session to the CS domain using the digit string of the Emergency Session Transfer Number for DRVCC.

Examples of typical use: Indicating the support to transfer the session to the CS domain in a SIP response to the SIP INVITE request and providing the dynamic Emergency Session Transfer Number for DRVCC digit string to be used to establish the CS call.

Security Considerations: Security considerations for this feature-capability indicator are discussed in clause 9 of IETF RFC 6809 [60].