\begin{thebibliography}{1}

\bibitem{rfc3261}
J.~Rosenberg, H.~Schulzrinne, G.~Camarillo, A.~R. 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{H.323}
{International Telecommunication Union}, \htmladdnormallink{``Visual telephone
  systems and equipment for local area networks which provide a non-guaranteed
  quality of service,''}{http://www.itu.int/} Recommendation H.323,
  Telecommunication Standardization Sector of ITU, Geneva, Switzerland, 2003.

\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{draft-levin-iptel-h323-url-scheme}
O.~Levin, \htmladdnormallink{``{H.323} {URL} scheme registration with
  {IANA},''}{http://www.ietf.org/internet-drafts/draft-levin-iptel-h323-url-sc%
heme-05.txt} internet draft, Internet Engineering Task Force, Nov. 2002.
\newblock Work in progress.

\bibitem{rfc3263}
J.~Rosenberg and H.~Schulzrinne, \htmladdnormallink{``Session initiation
  protocol {(SIP):} locating {SIP}
  servers,''}{http://www.rfc-editor.org/rfc/rfc3263.txt} RFC 3263, Internet
  Engineering Task Force, June 2002.

\bibitem{rfc2327}
M.~Handley and V.~Jacobson, \htmladdnormallink{``{SDP:} session description
  protocol,''}{http://www.rfc-editor.org/rfc/rfc2327.txt} RFC 2327, Internet
  Engineering Task Force, Apr. 1998.

\bibitem{rfc1890}
H.~Schulzrinne, \htmladdnormallink{``{RTP} profile for audio and video
  conferences with minimal
  control,''}{http://www.rfc-editor.org/rfc/rfc1890.txt} RFC 1890, Internet
  Engineering Task Force, Jan. 1996.

\end{thebibliography}
