RFC 2838 (rfc2838) - Page 2 of 6
Uniform Resource Identifiers for Television Broadcasts
Alternative Format: Original Text Document
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
