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IP over VBI (ipvbi) Charter Status: Concluded December, 1999 Chair(s): Dan Zigmond Description of Working Group: IP can be carried by many physical mechanisms. The vertical blanking interval of analog television signals (or VBI) is one more of these with the characteristic that it is unidirectional. It may therefore be only suitable for UDP/IP or multicast applications at present or we may build on this as other internet protocols are enhanced to allow unidirectional operation. A number of companies have already enhanced the functionality (in layers above the NABTS or WST, the two byte encoding standards for VBI) to include FEC, conditional access, encryption, file transfer etc, but each in a proprietary and incompatible way. This is a disincentive for systems to grow, and for the VBI to become widely used as a data transport mechanism. The broadcast industry is turning to digital TV, which will offer many Mbps broadcast data capacity, but this technology is in its infancy and still not widely available at the right price. VBI may therefore be viewed as an intermediate system (using well known, low cost and currently operating - for more than 10 years - technology) which will serve the data broadcast industry for a few years yet and probably for very many years in the less advanced countries - most countries actually. Sure the data rate is lower, but so is the cost. We already have transmissions, test equipment, test software, decoding software and chipsets. All we are talking of doing is upgrading the software to do a bit more. The reason for carrying IP is that it is a commonly available well known format to build on. The data broadcast industry then does not have to re-invent the wheel to use higher level protocols, but can simply layer existing protocols on IP. We expect IP and non-IP traffic to co-exist on VBI initially, but as the higher levels of internet are defined for broadcast use the IP traffic would dominate. The IPVBI group will define a standard mechanism for transmitting IP datagrams on top of both NABTS and WST VBI formats. The standard will include framing mechanisms, header compression, and an FEC system, all based on existing IETF standards where possible. Protocols above the IP layer (like streaming media and broadcast file transfer) will not be considered by IPVBI. Request for Comments:
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