An Improved GGSN Failure Restoration Mechanism for UMTS

Universal mobile telecommunications system (UMTS) provides packet-switched data services for mobile users. To efficiently deliver packets in the UMTS core network, the PDP contexts (i.e., the routing information) are maintained in the volatile storage (e.g., memory) of SGSN, GGSN, and UE. The GGSN routes packets between the UMTS core network and external data networks, and thus has heavy traffic and computation loading, which may result in PDP contexts lost or corrupted, and the QoS of the UMTS network may degrade significantly. To resolve this issue, 3GPP 23.007 proposes a mechanism for GGSN failure restoration. In this mechanism, the corrupted PDP contexts can be restored through the PDP Context Activation procedure. However, this incurs extra signaling cost to the network. To reduce the network signaling cost and delay for restoration of the corrupted PDP contexts, this paper proposes an improved mechanism “GGSN Failure Restoration” (GFR) with different backup algorithms. The analytic models and simulation experiments are conducted to evaluate GFR.Our study indicates that the GFR mechanism can significantly reduce the cost for the PDP context restoration. Phone Lin (M'02) received his BSCSIE degree and Ph.D. degree from National Chiao Tung University, Taiwan, R.O.C. in 1996 and 2001, respectively. From August 2001 to July 2004, he was an Assistant Professor in Department of Computer Science and Information Engineering (CSIE), National Taiwan University, R.O.C. Since August 2004, he has been an Associate Professor in Department of Computer Science and Information Engineering (CSIE), National Taiwan University, R.O.C. His current research interests include personal communications services, wireless Internet, and performance modeling. Dr. Lin is a Guest Editor for IEEE Wireless Communications special issue on Mobility and Resource Management. He is also an Associate Editorial Member for the WCMC Journal. Guan-Hua Tu received his B.S.C.S.I.E degree from National Central University, Taiwan, R.O.C., in 2001 and his Master degree in Computer Science from National Taiwan University, Taiwan, R.O.C., in 2003. He is currently a software engineer in MediaTek Inc. His resarch interests include personal communication services, mobile computing, and performance modeling.