GTP Software

The General Packet Radio Service (GPRS) Tunneling Protocol (GTP) portable software defines the protocol between the General Packet Radio Service Support Nodes (GSNs) within the GPRS backbone network. It includes both signaling and data transfer procedures. GTP is defined for the following interfaces:

  • The Gn interface between GSNs in a Public Land Mobile Network (PLMN)
  • The Gp interface between GSNs in different PLMNs

GTP tunnels multiprotocol packets through the GPRS backbone between GSNs. In the signaling plane, GTP specifies a tunnel control and management protocol allowing the Serving GPRS Support Node (SGSN) to provide GPRS services for a Mobile Station (MS). Signaling creates, modifies and deletes tunnels.

The User Datagram Protocol (UDP) is used as the path protocol to transfer signaling messages between GSNs. In the transmission plane, GTP uses a tunneling mechanism to carry user data packets.

Universal Mobile Telecommunications System (UMTS)

The GTP software product also supports the user plane protocol, GTP-u, between the Radio Network Controller (RNC) in the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) and the Third Generation SGSN (3G-SGSN). At this interface, the corresponding control plane is the Radio Access Network Application Protocol (RANAP).

Supporting GTP on the SGSN, GGSN, CGF, and RNC

The GTP product supports the:

  • GTP, in the control and user plane, between the 2G-SGSN and 2G-GGSN across the Gn and Gp interfaces
  • GTP, in the control plane and user plane, between the 3G-SGSN and 3G-GGSN across the Gn and Gp interfaces
  • GTP user plane (GTP-u) protocol between the 2G-SGSN and 2G-GGSN
  • GTP user plane (GTP-u) protocol between the 3G-SGSN and 3G-GGSN
  • GTP-u protocol between the 3G-SGSN and RNC
  • GTP protocol between the Call Detail Record (CDR) generating the GSNs and the Charging Gateway Functionality (CGF).


The GTP software product supports the GTP’ across the Ga interface to reliably transfer CDR-related information between the GPRS nodes, generating the CDRs (SGSN and GGSN) and CFG. This functionality applies to both GPRS and UMTS networks.

Product Information

The GTP software is portable C source code that can be compiled to run on any processor, under any operating system, and with any system architecture. The modular design and simple interfaces allow the GTP software to be easily ported into any environment.

Trillium GTP software enables telecom equipment manufacturers of SGSNs, GGSNs, RNCs, or other products to:

  • Accelerate time to market
  • Reduce development costs
  • Reduce project risk of internally developed GTP applications

Product deliverables consist of C source software, documentation, training information, a warranty and technical support.

Extensive debugging capabilities are provided. Where terminal printing support is available, debug printing can be enabled by using compile-time and run-time options to print information about protocol flows through the layer. Further, every function call contains a trace macro at its entry that can be mapped to print information about the function invocation. This is useful in embedded systems in which other symbolic debugging is unavailable.

Extensive error-checking and recovery mechanisms make the GTP software robust enough to deal with normal error conditions. Although error checks are important, disabling them will enhance the performance of the software. In this way, the GTP software permits the user to select the granularity of error checking using compile-time options.

Additional Specifications

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