W3C home > Mailing lists > Public > http-caching-historical@w3.org > February 1996

Ordered 'opqque' validators

From: David W. Morris <dwm@shell.portal.com>
Date: Fri, 2 Feb 1996 23:23:24 -0800 (PST)
To: HTTP Caching Subgroup <http-caching@pa.dec.com>
Message-Id: <Pine.SUN.3.90.960202231458.11710H-100000@jobe.shell.portal.com>

In prior discussions of opaque validators, someone suggested that
opaque validators should have an order property for the case where
a client is utilizing multiple caches which may not be synchronized.

Hence via proxy-A the client may receive the resource with
validator BCX and later check if still BCX is still OK to server
but ask proxy-B.  Proxy-B may have an out of date validator but
have no way of knowing.

After discussion in todays subgroup meeting, Jeff Mogul suggested
that the Date: header value could be used in conjunction with
the validator to establish the order.

On the surface, other than the possiblity that the Date: would
not have sufficient granularity and hence cause an unproductive
IF-VALID RTT, this seems OK. Does this seem reasonable?

If so, then the working notes draft proposal needs to be 
updated to describe the use of date: to establish order.

Dave Morris
Received on Saturday, 3 February 1996 07:43:16 UTC

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