C.17 Definition of feature-capability indicator g.3gpp.dynamic-stn

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

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

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 INVITE request or a SIP response to the SIP INVITE request, indicates support to transfer the session to the circuit switched (CS) domain using the dynamic STN (session transfer number) 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 SIP INVITE request or SIP response, the value is string containing the digit string in tel URI format of the dynamic STN 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.17-1 for g-3gpp-dynamic-stn.

Table C.17-1: ABNF syntax of values of the g.3gpp.dynamic-stn feature-capability indicator

g-3gpp-dynamic-stn = 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 dynamic STN.

Examples of typical use: Indicating the support to transfer the session to the CS domain in the SIP INVITE request and SIP response to the SIP INVITE request and providing the dynamic STN digit string to be used to establish the CS call instead of using the static STN to establish the CS call for the session transfer.

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