Section: 18.7 Correlation MSISDN
Content: A Correlation MSISDN (C-MSISDN) is an MSISDN (see clause 3.3) that is used for correlation of sessions at access transfer and to route a call from the IM CN subsystem to the same user in the CS domain. The C-MSISDN is equal to the MSISDN or the basic MSISDN if multinumbering option is used (see 3GPP TS 23.008[ Organization of subscriber data ]  [2], clause 2.1.3) of the CS access. Any MSISDN of a user that can be used for TS11 (telephony) in the CS domain which is not shared by more than one IMS Private Identity in an IMS CN subsystem, can serve as the user's C-MSISDN. The C-MSISDN is bound to the IMS Private User Identity and is uniquely assigned per IMSI and IMS Private User Identity. If A-MSISDN is available it shall be used as the C-MSISDN. For the definition of A-MSISDN refer to clause 18.9.