scope:

The present document is part of a series of Technical Specifications (TSs) that specify charging functionality and charging management in 3GPP networks. The 3GPP core network charging architecture and principles are specified in document TS 32.240 [1], which provides an umbrella for other charging management documents that specify:

- the content of the CDRs per domain and subsystem (offline charging),

- the content of real-time charging events per domain / subsystem (online charging);

- the functionality of online and offline charging for those domains and subsystems;

- the interfaces that are used in the charging framework to transfer the charging information (i.e. CDRs or charging events).

The complete document structure for these TSs is defined in TS 32.240 [1].

The present document specifies the offline, online and converged charging description for the IP Multimedia Subsystem (IMS), based on the functional descriptions of the IMS in TS 23.228 [200]. This charging description includes the offline, online and converged charging architecture and scenarios specific to IMS, as well as the mapping of common 3GPP charging architecture specified in TS 32.240 [1] onto IMS. It further specifies the structure and content of the CDRs and the charging events. The present document is related to other 3GPP charging TSs as follows:

- The common 3GPP charging architecture is specified in TS 32.240 [1];

- The parameters, abstract syntax and encoding rules for these CDR types are specified in TS 32.298 [51].

- A transaction based mechanism for the transfer of CDRs within the network is specified in TS 32.295 [54].

- The file based mechanism used to transfer the CDRs from the network to the operator's billing domain (e.g. the billing system or a mediation device) is specified in TS 32.297 [52].

- The 3GPP Diameter application that is used for IMS offline and online charging is specified in TS 32.299 [50].

- The services, operations and procedures of charging, using Service Based Interface are specified in TS 32.290 [45].

- The charging service of 5G system is specified in TS 32.291 [46].

Furthermore, requirements that govern the charging work are specified in TS 22.115 [101].