From: mitra@pandora.sf.ca.us (Mitra)
Subject: Re: Re urn2urc-00
Date: Wed, 20 Apr 1994 05:16:22 GMT
Message-Id: <CoJLBB.KLJ@pandora.sf.ca.us>
Terry -thanks for the questions - its good to see some more people have
read it well enough to find problems with it!
Terry Allen (terry@ora.com) wrote:
: Mitra, you write in draft-ietf-uri-urn2urc-00.txt, at (3),
: that the client locates a URN > URC resolution service to
: get from a URN to a URL. But you never explain why this
: is the way to go. I have imagined URCs as collections
: of information that would allow one to choose among URNs;
: the question of locating specific instances (URLs) of
: URNs should be much simpler. Would you expand on why you
: think this is reasonable?
I'm not quite sure I understand your question Terry, first did you
misprint URN for URL up above, I see a URC as a collection of info that
tell you about a URN and then typically gives you enough information
about specific URLs to allow either a user or a clever client to select
which URL to retrieve (based on cost, content-type etc).
: And (1st para under (3)), you write that the URN needs
: to contain enough info within it to locate the resolution
: service. This clearly isn't going to work. A publisher
: (he who assigns the URN) cannot know of services that
: spring up after the publication date, and shouldn't be
: relied upon to know of existing services.
What I propose is that a publisher needs to arrange for one or more
URN->URC resolution servers to provide resolution for the URN's they
allocate. In the scheme I proposed (and others are possible), DNS is
used on some portion of the URN to find the URN->URC server. So for
example if the URN was <urn:oreilly:123435456> the the client looks up
"oreilly.uri.int" in DNS and gets back the address of a resolution
service - that may or may not be run by oreilly.
The publisher doesnt need to know about hte services at publication
date. If at a later date they want to add a different URN->URC service,
they just arrange for oreilly.uri.int to return an alternative, or
additional address for this new service.
- Mitra