6 Functional description
23.2923GPPIP Multimedia Subsystem (IMS) centralized servicesRelease 17Stage 2TS
6.1 Common IMS Functions
6.1.1 P‑CSCF procedures
If CS media is present as part of the SIP/SDP message, the P‑CSCF shall not use this information when allocating resources for the media.
6.1.2 IMS ALG procedures
If CS media is present as part of the SIP/SDP message, the IMS ALG shall not use this information for media related functions such as IP address translation.
6.1.3 S‑CSCF procedures
If CS media is present as part of the SIP/SDP message, the S‑CSCF shall allow such media to be used for the service.
6.1.4 IBCF procedures
If CS media is present as part of the SIP/SDP message, the IBCF used in roaming scenarios shall not allocate resources for the media. The IBCF shall take CS media into account in other media control related functions.