This MIB module defines objects that are used to manage GTP Director Module. In the GPRS network, the APN is the identifier that specifies where the user is connecting. The APN identifies whether the network is a corporate network or a service provider network. The APN comprises of two parts, the network id and the operator id. The Single Access point feature enables the service provider to add new access-points to the GGSN without having to provision the HLR. The requests are sent by the SGSN to the same virtual APN. A virtual APN is not associated with any actual physical network. The GGSN processes the request and forwards the packet to the appropriate access-point that is specified in the PCO. The Single APN feature is supported only in Cisco GGSNs. The purpose of the GTP-Director is to provide a mechanism for service providers using non-Cisco GGSN to use the Single APN feature. This would enable the service providers to add access-point to the network without having to provision the HLR. This will be transparent to the SGSN. The mobile user initiates a connection request to the SGSN. The access-point name specified in the request is the virtual APN. The GTP-Director would resolve the access-point name and forward the request to the appropriate GGSN (real GGSN). +==+ +===+ +====+ ==== +===+ +====+ +===+ |MS|--|BSS|--|SGSN|--|PLMN|--|GDM|--|GGSN|--Gi-|PDN| +==+ +===+ +====+ ==== +===+ +====+ +===+ | | | | +====+ | |___|GGSN|------Gi | +====+ | | | | +====+ +===+ |_____|GGSN|--Gi-|PDN| +====+ +===+ The GTP-Director also provides load balancing across GGSNs. The GTP-Director uses the round-robin mechanism for providing load balancing. The Cisco GGSNs may use the GTP-Director, but is not necessary as they can use IOS-SLB ( Server Load Balancing ). Acronyms and terms: APN Access Point Name BSS Base Staion Subsystem GDM GTP Director Module GGSN Gateway GPRS Support Node Gi Reference point between GPRS and an external packet data network GPRS General Packet Radio Service HLR Home Location Register NMS Network Management System PCO Protocol Configuration Options PDN Packet Data Network PDP Packet Data Protocol PLMN Public Land Mobile Network MS Mobile Station SGSN Serving GPRS Support Node TID Tunnel Identifier