\begin{thebibliography}{1}

\bibitem{rfc2848}
S.~Petrack and L.~Conroy, \htmladdnormallink{``The {PINT} service protocol:
  Extensions to {SIP} and {SDP} for {IP} access to telephone call
  services,''}{http://www.rfc-editor.org/rfc/rfc2848.txt} RFC 2848, Internet
  Engineering Task Force, June 2000.

\bibitem{rfc3261}
J.~Rosenberg, H.~Schulzrinne, G.~Camarillo, A.~Johnston, J.~Peterson,
  R.~Sparks, M.~Handley, and E.~Schooler, \htmladdnormallink{``{SIP:} session
  initiation protocol,''}{http://www.rfc-editor.org/rfc/rfc3261.txt} RFC 3261,
  Internet Engineering Task Force, June 2002.

\bibitem{rfc2119}
S.~Bradner, \htmladdnormallink{``Key words for use in {RFCs} to indicate
  requirement levels,''}{http://www.rfc-editor.org/rfc/rfc2119.txt} RFC 2119,
  Internet Engineering Task Force, Mar. 1997.

\bibitem{rfc2779}
M.~Day, S.~Aggarwal, G.~Mohr, and J.~Vincent, \htmladdnormallink{``Instant
  messaging / presence protocol
  requirements,''}{http://www.rfc-editor.org/rfc/rfc2779.txt} RFC 2779,
  Internet Engineering Task Force, Feb. 2000.

\bibitem{rfc2434}
T.~Narten and H.~Alvestrand, \htmladdnormallink{``Guidelines for writing an
  {IANA} considerations section in
  {RFCs},''}{http://www.rfc-editor.org/rfc/rfc2434.txt} RFC 2434, Internet
  Engineering Task Force, Oct. 1998.

\bibitem{rfc2616}
R.~Fielding, J.~Gettys, J.~Mogul, H.~Frystyk, L.~Masinter, P.~Leach, and
  T.~Berners-Lee, \htmladdnormallink{``Hypertext transfer protocol --
  {HTTP/1.1},''}{http://www.rfc-editor.org/rfc/rfc2616.txt} RFC 2616, Internet
  Engineering Task Force, June 1999.

\end{thebibliography}
