ot allocate multicast addresses. SIP does not reserve resources, but can convey to the invited system what information is necessary to do SO. It can invite users to sessions with or without resource reservation. SIP relies upon SDP for notifying an endpoint of which codecs another endpoint supports. Any one of a myriad codecs can be identified with a string name and registered with Internet Corporation for Assigned Names and Numbers (ICANN is the successor to IANA, the Internet Assigned Names Authority). As such, SIP allows for interoperability with any registered (either standards-based or proprietary) codec. Although H.323 has a significant head start, it may favor to SIP because the latter is specifically designed for the application that is driving the teleconferencing market, Internet telephony. Anyone who is knowledgeable in HTTP will recognize much of SIP, and will find it intuitive. It seems likely that manufacturers will provide SIP as another option in their multiprotocol telephony gateway. If that is the case, the market will get to decide. Standards for Videoconferencing CHAPTER 7 REFERENCES "Advanced Video Coding For Generic Audiovisual Services (H.264)." International Telecommunications Union (ITU-T). May 2004. www.itu.int/ Yoshida, Junko. "H.264 Codec Jeopardizes MPEG-4's Ascendancy." EE Times. September 20, 2002. http://www.eetimes.com/story/OEG20020920S0049 Pechey, Bill. "Codec Frees Video Telephony." IT Week. April 4, 2003http://www.vnunet.com/analysis/1139947 Dalgic, Ismail and Fang, Hanlin. "Comparison of H.323 and SIP for IP Telephony Signaling," Photonics East, Boston, Massachusetts, September 20-22, 1999. Schulzrinne, Henning, and Rosenberg, Jonathan. "A Comparison of SIP and H.323 for Internet Telephony," Columbia University Technical Report CUCS-005-98, January 1998. Handley, M., Schulzrinne, H., Schooler, E., Rosenberg, J. "Network Working Group RFC: 2543 ACIRI Category: Standards Track SIP: Session Initiation Protocol," IETF March 1999. Korpi, Markku. "Exploring H.450 Needs and Usabilit