Re: Survey of URI implementation work (was: Re: Follow up...)

Keith Moore (moore@cs.utk.edu)
Sat, 08 Jul 1995 03:43:04 -0400


Message-Id: <199507080743.DAA21023@wilma.cs.utk.edu>
From: Keith Moore <moore@cs.utk.edu>
To: Peter Deutsch <peterd@bunyip.com>
Cc: Martin Hamilton <martin@mrrl.lut.ac.uk>, uri@bunyip.com, moore@cs.utk.edu
Subject: Re: Survey of URI implementation work (was: Re: Follow up...) 
In-Reply-To: Your message of "Fri, 07 Jul 1995 13:56:19 EDT."
             <9507071756.AA26767@expresso.bunyip.com> 
Date: Sat, 08 Jul 1995 03:43:04 -0400

Another one for the URI implementation list:

We have implemented a "resource catalog" (RC) server that provides
resolution services for various URIs: URNs, LIFNs, and URLs, which we
plan to demonstrate in Stockholm.  The server allows definition of
"assertions" about resources, cryptographically signed "certificates"
of those assertions, and location information for LIFNs.

It supports multiple data models (but you can query for just the ones
you're interested in), multiple versions of assertions, and multiple
asserters (the naming authority can allow third parties to add
assertions to a RC entry).

The location information for an object is maintained separately from
the characteristics of the object, and there are separate permissions
and rules for cacheing location data than for characteristics data.
So authorized file servers can update location data for the resources
(only for resources on their server) as they provide as they acquire
new resources and delete old ones.  

The server communicates via an RPC based protocol to a well-known
port.  It works over either UDP or TCP.  Strong authentication
(currently based on keyed-md5 and shared secrets) is required for
updates.

We plan to demonstrate both a web client and a http proxy server that
uses the RC server to acquire meta-information and/or location
information about a resource.

I'll have the RC server spec revised and available for ftp in a day or
so.

Keith