Subject: New Internet-Draft: DNS-Endpoint Discovery (http://www.ietf.org/internet-drafts/draft-snell-dnsepd-00.txt)

From: James Snell <[email-masked]>
Date: Mon, 25 Oct 2004 13:10:21 -0700

I wanted to drop a quick note about a new Internet-Draft I and my
colleague Andrew Donoho have submitted that we would like to discuss
both here on the list and at the upcoming face-to-face in Washington
D.C.

The DNS Endpoint Discovery, or DNS-EPD
(http://www.ietf.org/internet-drafts/draft-snell-dnsepd-00.txt) draft
proposes two new resource records used for the purpose of advertising
and discovering Web service endpoints using DNS.  The intro section of
the draft provides some of the background and motivation for the spec
so I'll skip that part of the discussion here.

There are two new RR's proposed, one representing a Web service
"Endpoint Reference" and the other allowing well-formed XML documents
to be stored in DNS. Examples of both are included below:

stockquotes._ws.example.com EPR 111 0 0 
                    services.example.com /services/sq 
                    {urn:myservices}MyStockQuotes 
                    http://services.example.com/services/sq.wsdl

stockquotes._ws.example.com XML 0 <EndpointReference xmlns="..." />

In the Web services world, an "Endpoint Reference" is a well known
construct that points to the network location where a Web service is
deployed and provides information about the service interface exposed
at that location.  The EPR record presented above provides a) the
location of the service expressed in terms of A/AAAA/SRV records, an
identifier for the service interface, and an indicator that more
information is available in the form of a WSDL document and an XML RR.

The XML RR is a straightforward record whose RDATA consists of two
fields.  The first is an unsigned byte whose value indicates the
encoding of the XML.  UTF-8 character encoding is the default.  The
second field is a well-formed XML document that is subject to certain
formatting restrictions (designed to minimize wasted space).  In many
respects the XML record shares the same basic semantics as the TXT
record with the exception that it is limited specifically to XML data.
 Please refer to the I-D for specifics on how the XML record is used
and interpreted in relation to DNS-EPD.

Our goal in submitting this draft is to begin the process of securing
feedback from the DNS expert community in order to determine:

1. Does the DNS expert community feel that it makes sense to leverage
DNS in this way

2. Does our design approach makes sense in terms of using new resource
records as opposed to using TXT records (I've been following the
recent discussions on this topic with great interest).

Thanks,

- James Snell
  IBM, Emerging Technologies
  [email-masked]
  [email-masked]

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