Subject: Drafts of interest to WebDAV...

From: "Lisa Dusseault" <[email-masked]>
Date: Mon, 8 Oct 2001 15:52:48 -0700

Two drafts on compression and delta transfers have been in progress for a
while.  Both are potentially useful for WebDAV software.  In case you
haven't seen them, I thought I'd forward the links and abstracts to the DAV
list.

http://www.ietf.org/internet-drafts/draft-mogul-http-digest-05.txt
http://www.ietf.org/internet-drafts/draft-mogul-http-delta-10.txt

Lisa

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A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title		: Instance Digests in HTTP
	Author(s)	: J. Mogul, A. van Hoff
	Filename	: draft-mogul-http-digest-05.txt
	Pages		: 12
	Date		: 04-Oct-01

HTTP/1.1 defines a Content-MD5 header that allows a server
to include a digest of the response body.  However, this is
specifically defined to cover the body of the actual
message, not the contents of the full file (which might be
quite different, if the response is a Content-Range, or
uses a delta encoding).  Also, the Content-MD5 is limited
to one specific digest algorithm; other algorithms, such as
SHA-1, may be more appropriate in some circumstances.
Finally, HTTP/1.1 provides no explicit mechanism by which a
client may request a digest.  This document proposes HTTP
extensions that solve these problems.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-mogul-http-digest-05.txt

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title		: Delta encoding in HTTP
	Author(s)	: J. Mogul, B. Krishnamurthy, F. Douglis,
                          A. Feldmann, Y. Goland, A. van Hoff, D.
Hellerstein
	Filename	: draft-mogul-http-delta-10.txt
	Pages		: 46
	Date		: 04-Oct-01

Many HTTP requests cause the retrieval of slightly modified
instances of resources for which the client already has a
cache entry.  Research has shown that such modifying
updates are frequent, and that the modifications are
typically much smaller than the actual entity.  In such
cases, HTTP would make more efficient use of network
bandwidth if it could transfer a minimal description of the
changes, rather than the entire new instance of the
resource.  This is called 'delta encoding.'  This
document describes how delta encoding can be supported as a
compatible extension to HTTP/1.1.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-mogul-http-delta-10.txt