INTERNET-DRAFT C. Finseth Firwood Consulting 28 March 2000 Referencing ISAN Identifiers with the Local Identifier (lid:) URI Scheme draft-finseth-isanlid-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This document expires 28 September 2000. Status of this Memo This memo provides information for the Internet community. This memo 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. Abstract This document specifies a method to use when referencing ISAN identifiers with the local identifier ("lid:") URI scheme. By specifying such referencing, broadcasts can avoid the overhead of sending the same information multiple times and implementation overhead can be reduced. Finseth [Page 1] INTERNET-DRAFT Referencing ISAN from lid: 28 March 2000 ISAN Identifiers (This section is written using the author's best judgement of how the system will eventually work. It will be updated as the in progress work completes.) These identifiers are the subject of a draft-ISO standard. Briefly, ISAN identifiers are assigned to complete audio/visual works such as television programs, movies, commercials, promotional spots, and so forth. Each version of each work is assigned its own identifer. ISAN Identifers are hexadecimal numbers written in the following format: AAAAAAAAAA-BBBB-CCCCC-D where - AAAAAAAAAA is a ten-digit hexadecimal number designating the work. For television series, one of these identifiers is assigned for the series as a whole. - BBBB is a four-digit hexadecimal number designating the episode of the series. For works that are not series, this value is always "0000". - CCCCC is a five-digit hexadecimal number designating the version. Each materiela change in the work is assigned its own version number. - D is a one-digit hexadecimal number that is a check digit. The upper/lower case of the letters a-f is not significant. Transmission ISAN identifers can appear in a number of places in a broadcast. The main locations will be in the electronic program guide and in the information describing the program currently on the air. Each transport (ATSC, DVB, etc.) will carry this information in a different way, so consult the documentation on those systems for specifics. Mapping Each receiver that implements the lid: URI scheme should take the already-transmitted ISAN identifier and use it as a source of lid: mapping information. The mapping is as follows. Finseth [Page 2] INTERNET-DRAFT Referencing ISAN from lid: 28 March 2000 For an ISAN identifier of the form: AAAAAAAAAA-BBBB-CCCCC-D act as if a lid: identifier of the form: lid://isan.smpte.org/AAAAAAAAAA/BBBB/CCCCC/D had been transmitted with the relevant mapping information. For example, if the ISAN identifier had been encountered in the electronic program guide, act as if the lid: had been transmitted with mapping information targeting the relevant electronic program guide slot. Matching With the above mapping in mind, lid: URI matching for references to ISAN identifiers can proceed exactly the same as any other lid: matching. There are, however, two special cases to consider. First, a lid: URI of the form: lid://isan.smpte.org/AAAAAAAAAA/BBBB or lid://isan.smpte.org/AAAAAAAAAA/BBBB/ should successfully match all versions of the material that the receiver is aware of. Second, a lid: URI of the form: lid://isan.smpte.org/AAAAAAAAAA or lid://isan.smpte.org/AAAAAAAAAA/ should successfully match all versions of all episodes of the material that the receiver is aware of. If the material is not a series (e.g., is a move, commercial, etc.), this form returns the same matches as the same as the match-all-versions form. Security Considerations This specification does not address security. It assumes that security and access control are handled by policies and procedures Finseth [Page 3] INTERNET-DRAFT Referencing ISAN from lid: 28 March 2000 implemented in the systems themselves. While this specification appears to provide a level of security by virtue of the fact that the only resources accessible by an application are those named in the broadcast stream, such is not the case. Absent other policies and procedures, an ill-behaved application can access resources by using device-specific mechanisms. References [1] "Uniform Resource Identifiers for Television Broadcasts", Mark Vickers, Dan Zigmond, 02/21/2000. (10914bytes), http://ietf.org/internet-drafts/draft-zigmond-tv-url-04.txt [2] "The Local Identifier (lid:) URI Scheme", C. Finseth, Dean Blackketter, Dan Zigmond, Gomer Thomas, Michael Dolan, 02/24/2000. (12122 bytes), http://ietf.org/internet-drafts/draft-blackketter-lid-00.txt [3] ten Kate, Warner; Thomas, Gomer; Finseth, Craig, "TV Broadcast URI Schemes Requirements", 11 March 1999. http://www.w3.org/TV/TVWeb/TVWeb-URI-Requirements-19990311 [4] "Guide to TV Broadcast URLs", C. Finseth, Gomer Thomas, 03/28/2000, http://ietf.org/internet-drafts/draft-finseth-guide-01.txt [RFC2396] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. Author's Address Craig A. Finseth Firwood Consulting 1343 Lafond St Paul MN 55104 Phone: +1 651-644-4027 Email: craig@firwood.net Full Copyright Statement Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation may be prepared, copied, published and Finseth [Page 4] INTERNET-DRAFT Referencing ISAN from lid: 28 March 2000 distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. 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