CURRENT_MEETING_REPORT_ Reported by Alan Emtage/BUNYIP Minutes of the Uniform Resource Identifiers Working Group (URI) The Uniform Resource Identifiers Working Group held three sessions in Columbus. These Minutes are separated on a per-session basis. Agenda o Uniform Resource Locators (URLs) - Session 1 o Uniform Resource Names (URNs) - Session 2 o Discussion of Other Necessary Objects - Session 3 Uniform Resource Locators (URLS) - Session 1 In order to try to prevent further confusion it was agreed that the following terminology would be used: For all the various UR* objects being discuss, the ``U'' would stand for ``Uniform'' and the ``R'' would stand for ``Resource''. URL is Uniform Resource Locator URN is Uniform Resource Name URI is Unform Resource Identifier (the collective name for UR*) A discussion of Tim Berners-Lee's current draft on Uniform Resource Locators (URLs) followed. The following points were made: o It is expected that in the near future character sets other than ASCII will need to be addressed. However in the short run it was decided that ASCII would be adequate for the task. The point was made by several European members of the Working Group that while other character sets would be necessary, it is important to get the current draft out and have the protocols discussed therein implemented. Wording to the effect that this matter has been addressed should be incorporated into the current text. The mechanisms defined need to be extensible to allow for expansion in this area. o The issue of ``fragments'' was raised. While the current draft addresses ``large scale'' objects such as entire files and services, it makes no attempt at defining sub-objects (such as a 1 paragraph, word or individual letter in text file). For example, how does one define a ``paragraph'' in a PostScript file, given that this is effectively an interpreted language? The general consensus was that we still do not have an adequate understanding of the underlying principles involved and that this discussion should be pursued on the mailing list. o The issue of OSI distinguished names in URLs was discussed. While further discussion is probably warranted, consensus held that this would probably be too ``heavy'' for the current proposals. o MIME encodings are also one possible avenue for describing network objects. It was agreed that the Working Group should work closely within the framework of existing RFCs for such descriptions. o It was agreed that the current URL draft should include an example URL specification for each access method defined in order to guide implementors. o Again the issue of partial URLs in the current draft was raised. It was agreed that while systems may choose to use such constructs internally, at no time would they be valid at the inter-system interface. Consensus was reached that stronger warnings need be placed in the current draft to that effect. It was also agreed that in the interests of time further discussions of the issue should be taken to the mailing list. The definition of partial URLs should also be moved to an appendix of the current document since they are not part of the official specification. Any algorithm for determining partial URLs should also be moved to the appendix. o The mechanism for registering new access methods with the Internet Assigned Numbers Authority (IANA) should be more prominently placed in the current draft. Also, some mechanism for defining experimental access methods should be included. o Several issues were raised which, it was decided, were better suited for the upcoming URN discussion since they fell into that domain. - Some form of integrity test was suggested (check digits) for URLs. It was decided that since URLs are inherently transitory in nature, that such tests would not be necessary. - Versioning - Security issues - Time to Live (TTLs) o It is expected that with this input the current draft can be submitted for Internet-Draft status within a few weeks following 2 the meeting. Uniform Resource Names (URNs) - Session 2 Before the meeting Cliff Lynch had posted an overview document to the mailing list titled ``A Framework for Identifying, Locating, and Describing Networked Information Resources'' and at the beginning of the session, he described the major points that the paper contained. John Kunze had also posted a document entitled ``Resource Citations for Electronic Discovery and Retrieval'' and made a short presentation about the paper. Peter Deutsch made a presentation as to a possible architecture for URNs. A ``spirited'' discussion followed as a result. There was much discussion as to what properties a URN should and should not have and the resulting fracas was in the best tradition of IETF ``consensus building''. It was agreed that while some of the underlying data of particular network objects changed (for example, a video feed), that the URN associated with such an object would remain essentially the same. However, the URNs for the underlying data would have to change as the data changed. Several suggestions for the type of information to be included in URNs were discussed and it was decided that a final decision would be made at the final session. Discussion of Other Necessary Objects - Session 3 After canvassing several members of the Working Group, the session started with a short presentation by one of the co-Chairs, Alan Emtage. It was proposed that the URN have a very simple structure. In order to be able to completely distinguish URNs from URLs the following structure was proposed: URN:: The string ``URN'' is part of the structure. is the unique identifier for the issuing authority. is the Uniform Resource String which is unique (as determined by the ID Authority) for that ID Authority. No assumptions may be made about the substructure of the URS which is effectively opaque to any entity other than the ID Authority. The ID Authority would be registered with the IANA to ensure uniqueness. 3 This proposal was endorsed and the corresponding document would be written by Alan Emtage, Jim Fullton and Chris Weider and submitted to the mailing list as soon as possible. It is hoped that the document can become an Internet-Draft at or before the Amsterdam meeting. A presentation was made by Rob Raisch which suggested some revisions to the above scheme. Questions about architecture were raised and it was suggested that the current draft architecture document from the Integration of Internet Information Resources (IIIR) Working Group be consulted. Further discussion illustrated the fact that the combination of URL & URN would not be sufficient for an effective infrastructure since much of the data needed by the user to determine desirability of an object located through a search was not present in these structures. These include such things as : o Versioning o Language o Character Sets o Representation (eg, PostScript, bitmaps, ASCII etc) o A whole array of non-static/non-text attributes Tim Berners-Lee, John Kunze and Michael Mealling made presentations as to how to handle this ``meta data'' or ``factoids''. It was decided that defining the semantics and syntax of these attributes would take careful work and should be the focus of upcoming meetings. Attendees Harald Alvestrand Harald.Alvestrand@delab.sintef.no Jules Aronson aronson@nlm.nih.gov Karl Auerbach karl@empirical.com Paul Barker p.barker@cs.ucl.ac.uk Robert Beer r-beer@onu.edu Tim Berners-Lee timbl@info.cern.ch Jodi-Ann Chu jodi@uhunix.uhcc.hawaii.edu William Chung whchung@watson.ibm.com David Conklin conklin@jvnc.net James Conklin jbc@bitnic.educom.edu Naomi Courter naomi@concert.net John Curran jcurran@nic.near.net Brent Curtiss bcurtiss@magnuss.ocs.ohio-state.edu Mark Davis-Craig mad@merit.edu Peter Deutsch peterd@bunyip.com Thomas DeWitt tdewitt@osi.ncsl.nist.gov Dale Dougherty dale@ora.com Alan Emtage bajan@bunyip.com 4 Urs Eppenberger eppenberger@switch.ch Roger Fajman raf@cu.nih.gov Jill Foster Jill.Foster@newcastle.ac.uk Steven Foster foster@cs.unr.edu Jim Fullton Jim.Fullton@cnidr.org Kevin Gamiel kevin.gamiel@concert.net Joan Gargano jcgargano@ucdavis.edu Greg Gicale gicale@ohio.gov Deborah Hamilton debbie@qsun.att.com Susan Harris srh@umich.edu Alisa Hata hata@cac.washington.edu Russ Hobby rdhobby@ucdavis.edu Ellen Hoffman ellen@merit.edu Susan Horvath shorvath@merit.edu Inna Il'yasova ilyasova@meg.uncg.edu Erik Jul jul@oclc.org Scott Kaplan scott@wco.ftp.com Michael Khalandovsky mlk@ftp.com John Klensin klensin@infoods.unu.edu Jim Knowles jknowles@binky.arc.nasa.gov Andrew Knutsen andrewk@sco.com Edward Krol e-krol@uiuc.edu John Kunze jak@violet.berkeley.edu Ronald Lanning lanning@netltm.cats.ohiou.edu Hock-Koon Lim lim@po.cwru.edu Clifford Lynch calur@uccmvsa.ucop.edu Bruce Mackey brucem@cinops.xerox.com Samir Malak malaks@alice.uncg.edu Gary Malkin gmalkin@xylogics.com Janet L. Marcisak jlm@ftp.com April Marine april@atlas.arc.nasa.gov Ignacio Martinez martinez@rediris.es Michael Mealling michael@fantasy.gatech.edu Keith Moore moore@cs.utk.edu Jim Naro jnaro@nic.near.net Mark Needleman mhn@stubbs.ucop.edu Clifford Neuman bcn@isi.edu Bill Norton wbn@merit.edu Masataka Ohta mohta@cc.titech.ac.jp Geir Pedersen Geir.Pedersen@usit.uio.no Pete Percival percival@indiana.edu Charles Perkins perk@watson.ibm.com Marsha Perrott mlp+@andrew.cmu.edu Cecilia Preston cpreston@info.berkeley.edu Robert Raisch raisch@ora.com Joyce K. Reynolds jkrey@isi.edu Francois Robitaille francois.robitaille@crim.ca Richard Rodgers rodgers@nlm.nih.gov Charlie Smith crsmith@osvi.edu Jane Smith Jane.Smith@cnidr.org Patricia Smith psmith@merit.edu Sue Smith smiths.es.net Karen Sollins sollins@lcs.mit.edu Wayne Tackabury wayne@cayman.com 5 Matt Tuttle snodgras@cren.net Ruediger Volk rv@informatik.uni-dortmund.de Janet Vratny janet@apple.com Chris Weider clw@merit.edu Les Wibberley lhw24@cas.org Richard Wiggins wiggins@msu.edu 6