Pre-biller in internet protocol multimedia subsystem (IMS) charging gateway function (CGF)

In a telecommunications network, apparatus for performing the processing of online and offline billed telecommunications calls, comprising:

• means, responsive to receipt of a telecommunications call session, involving a plurality of network elements, for building up a plurality of charging data records that are missing call cost data;
• means, responsive to said building up a plurality of charging data records, for sending said charging data records to a charge gateway function for providing said missing call cost data;
• said charging gateway function for transmitting charging data records including said missing call cost data to a billing system;
• said charging gateway function comprising a pre-billing module, and a charge data record routing and filtering module, and a charging data record correlation function;
• said charging data record correlation function for assembling all charging data records pertaining to one call into a single charging data record;
• said routing and filtering module for determining whether rating information is needed and for requesting said pre-billing module to request said rating information;
• said pre-billing module for requesting rating information from a rating engine and for completing said charging data record in response to receipt of said rating information;
• said routing and filtering module for routing completed charging data records to appropriate files of a billing system.