ons, 2009. [5] WiMAX Forum Network Architecture Stage 2: Architecture Tenets, Reference Model and Reference Points Release 1.5, September 2009. <http://www.wimaxforum.org/resources/documents/technical/release> [6] Recommendations and Requirements for Networks based on WiMAX Forum Certified Products, Release 2.0, May 2009 <http://www.wimaxforum.org/resources/documents/technical/release> 3GPP TS 23.401, General Packet Radio Service (GPRS) Enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN), March 2009. (ftp://ftp.3gpp.org/specs/). [8] Virtual Private Network (VPN). <http://en.wikipedia.org/wiki/Virtual_private_network>. [9] IETF RFC 3344, in: C. Perkins (Ed.), IP Mobility Support for IPv4, August 2002. [10] IETF RFC 2460, S. Deering, R. Hinden, Internet Protocol, Version 6 (IPv6) Specification, December 1998. WiMAX Forum Mobile System Profile Specification Release 1.5, February 2009. <http://www. imaxforum.org/resources/documents/technical/release> [12] IEEE Std 802.16-2009, IEEE Standard for Local and Metropolitan Area Networks - Part 16: Air Interface for Broadband Wireless Access Systems, May 2009. [13] Kamran Etemad, "Overview of Mobile WiMAX Technology and Evolution", IEEE Communications Magazine, October 2008. [14] Jeffrey G. Andrews, Arunabha Ghosh, Rias Muhamed, Fundamentals of WiMAX: Understanding Broadband Wireless Networking, first ed., Prentice Hall, 2007. [15] Loutfi Nuaymi, WiMAX: Technology for Broadband Wireless Access, first ed., John Wiley & Sons Ltd, 2007. [16] IETF RFC 2138, C. Rigney, A. Rubens, W. Simpson, S. Willens, Remote Authentication Dial in User Service (RADIUS), April 1997. [17] IEFT RFC 3588, P. Calhoun, J. Loughney, E. Guttman, G. Zorn, J. Arkko, Diameter Base Protocol, September 2003. CHAPTER 2 WiMAX Network Architecture [18] Yan Zhang, Jun Zheng, Miao Ma, Handbook of Research on Wireless Security, Information Science Publishing 2008. [19] 3GPP TS 11.11, Specification of the Subscriber Identity Module - Mobile Equipment (SIM-ME) Interface, June 2003. (ftp:/