Uniform Resource Identifiers for Television Broadcasts
RFC 2838
Document | Type |
RFC - Informational
(May 2000; No errata)
Was draft-zigmond-tv-url (individual)
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Authors | Dan Zigmond , Mark Vickers | ||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 2838 (Informational) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group D. Zigmond Request for Comments: 2838 WebTV Networks, Inc. Category: Informational M. Vickers Liberate Technologies, Inc. May 2000 Uniform Resource Identifiers for Television Broadcasts Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. 1. Introduction World-Wide Web browsers are starting to appear on a variety of consumer electronic devices, such as television sets and television set-top boxes, which are capable of receiving television programming from either terrestrial broadcast, satellite broadcast, or cable. In this context there is a need to reference television broadcasts using the URI format described in [RFC 2396]. This document describes a widely-implemented URI scheme to refer to such broadcasts. 2. Television URI The basic structure of a television URI is: tv:<broadcast> where broadcast is a description of the data source. The description takes the form of a DNS-style identifier for a particular broadcaster or television network. For example: tv:wqed.org the WQED station tv:nbc.com the NBC network Zigmond & Vickers Informational [Page 1] RFC 2838 URIs for TV Broadcasts May 2000 3.1. Scheme-only form A simplest form of the "tv:" URI scheme is used to refer to the "current" or "default" channel: tv: This URI refers to whichever television broadcast is currently being received by the device. It is often used in combination with HTML content that is actually being broadcast along with the audio and video, where the meaning of "current broadcast" is quite unambiguous (because it is the broadcast along with which the content containing the URI was received). This is in fact the most common usage of the "tv:" scheme today, and is explicitly referenced by the recently published specification of the Advanced Television Enhancement Forum [ATVEF 1.1]. 3.2 DNS-style identifiers Television broadcasts traditionally have been identified in a variety of ways. All terrestrial television broadcasters are assigned call signs (such as "KDKA" or "WQED") to identify their signal. These are generally assigned by national authorities (such as the Federal Communications Commission in the United States) and are world unique. The global namespace is managed by the International Telecommunications Union, which assigns portions to member countries (see [ITU RR]). Many modern television networks are not broadcasted over-the-air, but available only through cable or satellite subscriptions. The identifiers for these networks (such as the familiar "CNN" and "HBO") are not regulated at this time. In some countries, even over-the-air broadcasters use these sorts of identifiers, rather than call signs. Unfortunately, these two namespaces overlap, with most network identifiers also being valid call signs. Furthermore, network identifiers are not world unique, and many cases exist of name collisions. (For example, both the Australian Broadcast Corporation and the American Broadcasting Company identify themselves as "ABC".) In order to ensure uniqueness, the "tv:" scheme uses DNS-style identifiers for all broadcast streams. Because these build on the existing registration system for DNS hostname, all name collisions can be resolved through the existing DNS dispute resolution processes. Zigmond & Vickers Informational [Page 2] RFC 2838 URIs for TV Broadcasts May 2000 In the simplest form, domain names themselves are used as broadcast identifiers. For example: tv:abc.com the American Broadcast Company tv:abc.co.au the Australian Broadcast Corporation In some cases, networks have multiple broadcast streams that need to be distinguished. This is also handled in DNS style: tv:east.hbo.com HBO East tv:west.hbo.com HBO West It is important to note that these DNS-style identifiers need not match real hostnames; they should not be resolved to IP addresses using DNS. Thus, using the terms as defined in RFC 2396, the "tv:" scheme is a Uniform Resource Identifier and not a Uniform Resource Locator. In order to support these identifiers in a "tv:" URI, a receiver must implement a means to map known identifiers to frequencies. The natureShow full document text