A GTP stateful inspection method based on network processor

GPRS tunnelling protocol (GTP) is the protocol used in general packet radio service (GPRS) Core network, and it will also be used in the 3rd Generation (3G) network. In view of that few study concerns about GTP stateful inspection at present, this paper introduces a method of GTP stateful inspection on the foundation of analyzing the GTP protocol and provides the implementation of the method based on Intel network processor IXP28xx. In the implementation, the method employs a data structure adapting to the memory managing and accessing of the network processor. Furthermore, a new hash algorithm named hash_fold_16_4 algorithm is put forward to achieve fast index to the data structure. Experiment results show that the method is practicable and effective.