Section: 5.2.1.3 Transfer of CDR files via Bx
Content: The CGF is responsible for persistent CDR storage, for preparing CDR files and transferring them to the BD via the Bx reference point. To this end, the CGF provides one or more files on which to store the CDRs after potential reformatting to comply with the Bx file format specified in TS 32.297[ Telecommunication management; Charging management; Charging Data Record (CDR) file format and transfer ]  [52]. The CDRs may be routed to one of several simultaneously open files inside the CGF depending on certain CDR parameters, such as CDR type, or on other criteria such as the originating CDF. CDR files are closed on the CGF based on certain operator configured parameters, for example: - file size limit, - file duration (time) limit, - time of day, - maximum number of CDRs. This implies that the closure of a CDR file occurs asynchronously to the reception of CDRs on the CGF. When a CDR file is closed, the CGF must assure that a new CDR file is available to store incoming CDRs in line with the CDR routing facility described above. Once CDR files are closed, they are ready for transfer to the BD. The CGF shall support both "push" transfer mode (i.e. CGF triggers and controls file transfer to BD) and "pull" transfer mode (i.e. BD triggers and controls file transfer). In push mode, the CGF uploads the files to the BD according to operator specified parameters, such as time of day, number of available files, etc. In pull mode, the BD may request the files from the CGF at any point in time at the discretion of the BD. For all procedures involved in CDR reception, processing and storing, the CGF shall be capable of complying with near real-time requirements. Details on the protocol application for the open Bx interface and the functionality of the CGF can be found in TS 32.297[ Telecommunication management; Charging management; Charging Data Record (CDR) file format and transfer ]  [52]. The semantics and formal description of the CDR parameters are specified in TS 32.298[ Telecommunication management; Charging management; Charging Data Record (CDR) parameter description ]  [51].