This MIB module manages the charging related function on the GGSN node of a GPRS system. The following diagram illustrates a simplified GPRS logical architecture with the interface name denotations: +==+ +===+ +====+ +====+ +===+ |MS| +==+ +===+ +====+ +====+ +===+ \ / Ga Ga \ +==+ / |CG| +==+ Charging information in GPRS is collected for each MS by SGSNs and GGSNs that are serving that MS. The GGSN collects charging information for each MS based on both external data network usage and the GPRS network resources. Acronyms and terms: APN Access Point Name BSS Base Station System CCA Credit Control Answer CDR Call Detail Record CID Charging Identification CG Charging Gateway CGF Charging Gateway Functionality CGG Charging Gateway Group. DCCA Diameter Credit Control Application ETSI European Telecommunications Standards Institute Ga Name of the interface between SGSN/GGSN and CG Gi Name of the interface between GGSN and PDN Gn Name of the interface between GGSN and SGSN G-CDR Gateway GPRS Support Node-Call Detail Record GGSN Gateway GPRS Support Node GPRS General Packet Radio Service GSM Global System for Mobile communication GTP GPRS Tunneling Protocol GTP' GTP enchanced for charging IE Information Element MS Mobile Station PDN Packet Data Network PDP Packet Data Protocol SGSN Serving GPRS support Node TOS Type of Service. PSD Persistance Storage Device. PTC Packet Transfer Command. EPC Evolved Packet Core PGW PDN Gateway SGW Serving Gateway SPGW When a single physical EPC Gateway acts as both SGW and PGW for a session, then that session is said to be in SPGW mode.