2327. April. [8] Nakajima, N., A. Dutta, S. Das, and H. Schulzinne. 2003. Handoff delay analysis and measurement for SIP based mobility in IPv6. International conference on communications (ICC'03) 26: 1085-89. May. [9] Campbell, A.T., J. Gomez, S. Kim, A.G. Valko, and C Wan. 2000. Design, implementation, and evaluation of cellular IP. IEEE Personal Communications 7(4): 42-49. August. [10] Jung, J.W., R. Mudumbai, D. Montgomery, and H.K. Kahng. 2003. Per- formance evaluation of two layered mobility management using mobile IP and session initiation protocol. Global Telecommunication Conference 2003 (GLOBECOM'03) IEEE3: 1190-94, San Francisco, USA. [11] Choudhary, U., E. Perl, and D. Sidhu. 2001. Using T.38 and SIP for real- time fax transmission over IP networks. 26th Annual IEEE Conference on Local Computer Networks (LCN'01) 74 IEEE November. [12] Eun-Chul Cha, Hyoung-Kee Choi, and Sung-Jae Cho. 2007. Evaluation of security protocols for the session initiation protocol. In Proceedings IEEE 611-16. [13] Dritsas, S., J. Mallios, M. Theoharidou, G. F. Marias, and D. Gritza- lis. Threat analysis of the session initiation protocol regarding spam. In Proceedings of IEEE International Conference on Performance, Com- puting, and Communications Conference, IPCCC 2007, New Orleans, Louisiana, USA, pp. 426-33. April 11-13. [14] Dierks, T., and C. Allen. 1999. The TLS protocol version 1.0. RFC 2246. January. C 2009 by Taylor & Francis Group, LLC SIP Security and Quality of Service Performance [15] Kent, S., and R Atkinson. 1998. Security architecture for the internet protocol. RFC 2401. November. [16] Chown, P. 2002. Advanced Encryption Standard (AES) cipher suites for Transport Layer Security (TLS). RFC 3268. June. [17] Rosenberg, J., and H Schulzrinne. 2002. SIP: Locating SIP Servers. RFC 3263. June. [18] Rosenberg, J., H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler. 2002. RFC 3261 SIP: Session Initiation Protocol. http://www.faqs.org/rfcs/rfc3261.html. [19] Duanfeng, S., L. Q