4, 3rd Generation Partnership Project (3GPP), December 2011. 81. 3GPP. Policy and Charging Control (PCC) over S9 reference point; Stage 3. TS 29.215, 3rd Generation Partnership Project (3GPP), March 2012. IPv6 in 3GPP Networks 82. 3GPP. Telecommunication management; Charging management; Charging architecture and principles. TS 32.240, 3rd Generation Partnership Project (3GPP), April 2011. 83. 3GPP. Telecommunication management; Charging management; Packet Switched (PS) domain charging. TS 32.251, 3rd Generation Partnership Project (3GPP), December 2011. 84. 3GPP. Customised Applications for Mobile network Enhanced Logic (CAMEL) Phase 4; Stage 2. TS 23.078, 3rd Generation Partnership Project (3GPP), December 2011. 85. 3GPP. Customised Applications for Mobile network Enhanced Logic (CAMEL) Phase X; CAMEL Appli- cation Part (CAP) specification. TS 29.078, 3rd Generation Partnership Project (3GPP), June 2010. 86. 3GPP. Telecommunication management; Charging management; Charging Data Record (CDR) parameter description. TS 32.298, 3rd Generation Partnership Project (3GPP), March 2012. 87. GSMA,. TAP3 Format Specification. PRD TD.57 30.3, GSM Association (GSMA), May 2012. 88. Farinacci, D., Li, T., Hanks, S., Meyer, D., and Traina, P. Generic Routing Encapsulation (GRE). RFC 2784, Internet Engineering Task Force, March 2000. 89. Lau, J., Townsley, M., and Goyret, I. Layer Two Tunneling Protocol - Version 3 (L2TPv3). RFC 3931, Internet Engineering Task Force, March 2005. 90. Perkins, C. IP Encapsulation within IP. RFC 2003, Internet Engineering Task Force, October 1996. 91. Chiba, M., Dommety, G., Eklund, M., Mitton, D., and Aboba, B. Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS). RFC 5176, Internet Engineering Task Force, January 2008. 92. Zorn, G. Microsoft Vendor-specific RADIUS Attributes. RFC 2548, Internet Engineering Task Force, March 1999. 93. Calhoun, P., Zorn, G., Spence, D., and Mitton, D. Diameter Network Access Server Application. RFC 4005, Internet Engineering Task 