13 Interoperability of IMS Centralized Services (ICS) over II-NNI

29.1653GPPInter-IMS Network to Network Interface (NNI)Release 18TS

13.1 General

In order to assure the end-to-end service interoperability through the Inter-IMS Network to Network Interface (II-NNI), the associated service of the IMS Centralized Services (ICS) may be supported on the II-NNI between two IMS networks. The support of ICS is based on agreement between operators.

If ICS is supported, the related procedures from the 3GPP TS 24.292 [121] and 3GPP TS 29.292 [130] shall be applied with the requirements in the clause 13.2 due to the crossing of the II-NNI.

13.2 IMS Centralized Services (ICS)

Service specific requirements in accordance with 3GPP TS 24.292 [121] and 3GPP TS 29.292 [130] shall be supported over the II-NNI.

The "g.3gpp.ics" media feature tag in the Contact header field as specified in annex B of 3GPP TS 24.292 [121] shall be supported at the roaming II-NNI.

The "g.3gpp.accesstype" media feature tag in the Contact header field as specified in annex B of 3GPP TS 24.292 [121] shall be supported at the roaming II-NNI.

The "g.3gpp.icsi-ref" media feature tag as specified in 3GPP TS 24.229 [5] the value for the IMS Multimedia Telephony Communication Service as specified in 3GPP TS 24.173 [31] shall be supported at the roaming II-NNI.

An Accept-Contact header field and a Reject-Contact header field including the media feature tag "g.3gpp.accesstype" and the media feature tag "g.3gpp.ics" in any combination in the INVITE request shall be supported at the roaming II-NNI.

The Target-Dialog header field in the INVITE request shall be supported at the roaming II-NNI.

The P-Early-Media header field in the INVITE request and in non-100 provisional responses to the INVITE request shall be supported on the roaming II-NNI.

The Reason header field containing the protocol value "Q.850" and the header field parameter "cause" with a various set of values in the CANCEL request, the BYE request and in 4xx responses and 6xx responses to the INVITE request shall be supported at the roaming II-NNI.

The REFER request with the "method" SIP URI parameter set to the value "BYE" or "INVITE" or without the "method" SIP URI parameter in the Refer-To header field as specified in 3GPP TS 24.292 [121] shall be supported at the roaming II-NNI.

The Event header field containing the event package name "conference" and the Accept header field with "application/conference-info+xml" in a SUBSCRIBE request shall be supported at the roaming II-NNI.

The Allow-Event header field with "application/conference-info+xml" in an INVITE request shall be supported at the roaming II-NNI.

The "application/conference-info+xml" MIME body and the Event header field containing the event package name "conference" in a NOTIFY request shall be supported at the roaming II-NNI.

NOTE: Supplementary services as specified in clause 12 can be supported based on agreement between operators.