7.5.12 Communication Waiting (CW)

29.1633GPPInterworking between the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networksTS

7.5.12.0 General

The protocol specification of the Communication Waiting supplementary service is described in 3GPP TS 24.615 [111].

7.5.12.1 Interworking at the I-MGCF

With regard to the backward messages of the Call Waiting PSTN/ISDN supplementary service, the following mapping is valid:

Table 7.5.12.1: Mapping of ISUP messages to SIP Massages

Message Received from BICC/ISUP

Message sent to SIP

ACM or CPG with generic notification indicator "Call is a waiting call" (NOTE 1).

180 Ringing with an Alert-Info header field set to "urn:alert:service:call-waiting" (NOTE 2).

NOTE 1: The coding shall be in accordance with ITU-T recommendation Q.733 [42].

NOTE 2: The coding shall be in accordance with IETF RFC 7462 [107].

7.5.12.2 Interworking at the O-MGCF

With regard to the backward messages of the Communication Waiting service, the following mapping is valid:

Table 7.5.12.2: Mapping of SIP messages to ISUP messages

Message sent to ISUP

Message Received from SIP

ACM or CPG with generic notification indicator "Call is a waiting call" (NOTE 1).

180 Ringing with an Alert-Info header field set to "urn:alert:service:call-waiting" (NOTE 2).

NOTE 1: The coding shall be in accordance with ITU-T recommendation Q733 [42].

NOTE 2: The coding shall be in accordance with IETF RFC 7462 [107].