This MIB module manages the GPRS Tunnelling Protocol (GTP) on GGSN and SGSN. GPRS provides wireless access to packet data network on the GSM infrastructure. The following diagram illustrates a simplified GPRS logical architecture with the name of inter-node interface: + | a PLMN +======+ +======+ | | | SGSN | | AAA | | | +======+ +======+ | | | | | | Gn SGi | | | | | |+====+ +====+ +=====+ +======+ +======+ | +===+ || TE |-R-| MT |-| BSS |-| SGSN |-Gn-| GGSN |-|-Gi-|PDN| |+====+ +====+ +=====+ +======+ +======+ | +===+ | | | | | | + Gp | + | +====+ +=====+ +======+ | | | MS | | +====+ +=====+ +======+ | | | | other PLMN | + GTP is the protocol between GSN nodes (GSN peers) in the GPRS backbone network. It includes both the GTP signalling and data transfer procedures. GTP is used both on the Gn interface, i.e. the interface between GSN peers with in a PLMN, and the Gp interface between GSN peers in different PLMNs. SGSN is the serving GPRS support node, it responsible for the delivery of data packets from and to the MS within its service area. GGSN is the gateway GPRS support node, it provides interworking with external PDN and is connected with SGSNs via an IP-based GPRS backbone network. The GTP protocol is implemented only by SGSNs and GGSN. A PDP Context is an information set maintained by MS and GSNs which describes the mobile wireless service call or session. A Qos Profile is associated with each PDP context which defines multiple attributes like precedence, delay, reliability, peak throughput and mean throughput. Based on the precedence, delay and mean throughput an user is classified into one of the three Qos classes: Best Effort, Normal and Premium. Mean throughput is measured at the Gi and R reference points in units of octets per second. It specifies the average rate at which data is expected to be transferred across the GPRS network during the remaining lifetime of an activated PDP context. A MAP converting GSN is responsible for converting GTP messages to and from MAP messages. This helps in the communication with HLR. Acronyms and terms: APN Access Point Name BSS Base Station Subsystem CG Charging Gateway COA Change of Authorization ETSI European Telecommunications Standards Institute GDM GTP Director Module Gi Reference point between GPRS and an external packet data network. Gn the interface between GSNs within a PLMN Gp the interface between GSNs in different PLMNs GGSN Gateway GPRS Support Node GPRS General Packet Radio Service GSM Global System for Mobile communication GSN GPRS Support Node G-PDU GTP PDU HLR Home Location Register MAP Mobile Application Protocol MME Mobility Management Entity MS Mobile Station = TE + MT MT Mobile Termination NMS Network Management System PDN Public Data Network PDP Packet Data Protocol PDU Protocol Data Unit PGW PDN Gateway PLMN Public Land Mobile Network R Reference point between a non-ISDN compatible TE and MT. SAE System Architecture Evolution SGSN Serving GPRS Support Node SGW Serving Gateway TE Terminal Equipment T-PDU the payload of G-PDU VRF Virtual routing and forwarding AAA Authentication, Authorization and Accounting eNodeB Evolved Node B RNC Radio Network Controller