Emulation of the GTP protocol with NS-2

Using an emulation capability in network simulation provides the ability for real-world traffic to interact with a simulation. With an emulator a real protocol implementation can be subjected to packet dynamics that are difficult to reproduce reliably in real conditions. The Ns-2 simulator, a publicly available network simulator, provides the emulation facility. This paper describes the design and the implementation of a real-time interactive GPRS Tunneling Protocol (GTP) emulator developed under the Ns-2 environment. This tool is used to emulate the behavior of a Service GPRS Support Node (SGSN), a router used in the back-bone network of the GPRS and UMTS system. It allows to make performance tests on a Gateway GPRS Support Node (GGSN), without the need of the radio access part of these networks.