Today's best questions come from two attendees of recent Network World VoIP sessions led by Steve. In related questions, Bill asks, " What will win as the de facto standard - H.323 or SIP? " and Dan asks, " Where are we with regards to interoperability between SIP and H.323? "
Session Initiation Protocol (SIP) is a standard introduced by the Internet Engineering Task Force in 1999 to carry voice over IP. Since it was created by the IETF, it approaches voice and multimedia from the Internet, or IP, perspective. H.323 emerged around 1996, and as an International Telecommunication Union standard was designed from a telecommunications perspective. Both standards have the same objective - to enable voice and multimedia convergence with IP protocols.
As the older standard, H.323 has been embraced by many of the early VoIP players, so it has the advantage of being implemented first. SIP more easily allows applications to be developed because of its origins and has been gaining in popularity, especially in North America and with new entrants into the VoIP market.
We don't believe either protocol will " win. " In fact, we believe that protocol wars waste a lot of good energy that could be better spent evolving the standards. And both protocols are evolving to offer more features.
In interoperability between the two, the industry is making slow but sure progress. Interoperability must first happen between vendor implementations of the same protocol (SIP-to-SIP and H.323-to-H.323) and then between protocols.
Many vendors now support both protocols, as their customers want flexibility to choose based on different needs. Some, like CommWorks, even support an interoperability module between the protocols to support service interworking. We believe both standards have their advantages and disadvantages, and fully support efforts to make the two interoperable.
RELATED LINKS
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Network World, 07/01/02
Steve Taylor is President of Distributed Networking Associates and Publisher/Editor-in-Chief of Webtorials.Com. For more detailed information on most of the topics discussed in this newsletter, connect to Webtorials.Com, the first Web site dedicated exclusively to market studies and technology tutorials in the Broadband Packet areas of Frame Relay, ATM, and IP.
Larry Hettick is an independent consultant, with 19 years of experience in telecommunications and data communications marketing and product management for service providers and equipment vendors. He can be reached at larry@larryhettick.com
You can reach the authors at taylor@webtorials.com or larry@larryhettick.com.
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