- From: Paul Leach <paulle@microsoft.com>
- Date: Tue, 16 Apr 1996 13:31:55 -0700
- To: "'koen@win.tue.nl'" <koen@win.tue.nl>
- Cc: "'fielding@avron.ICS.UCI.EDU'" <fielding@avron.ICS.UCI.EDU>, "'http-caching@pa.dec.com'" <http-caching@pa.dec.com>, "'jg@w3.org'" <jg@w3.org>
I object to caches assigning variant-ids. If they're needed for pre-emptive content negotiation by caches based on what is the Alternates header, then the origin-server should generate variant-ids for each alternate and return them in the alternates header. It'll be a lot simpler that way. >---------- >From: koen@win.tue.nl[SMTP:koen@win.tue.nl] >Sent: Tuesday, April 16, 1996 12:31 AM >To: Paul Leach >Cc: fielding@avron.ICS.UCI.EDU; koen@win.tue.nl; >http-caching@pa.dec.com; jg@w3.org >Subject: Re: Variant-ID proposal > >Paul Leach: > [Koen Holtman:] >>>If you have two orthogonal mechanisms, you can't have them share the >>>same space in the Cval: header. > >>This sounds to me like you're confusing protocol mechanisms and >>implementation mechanisms. There are two orthogonal protocol mechanisms >>here, but in any server, I would imagine only one implementation > ^^^^^^^^^^^^^ ^^^^^^^^ >>mechanism, which would _indeed_ share the same variant-id scheme. Hence, >>I don't agree that the design principle you invoke applies to this case. > >I think the response I just sent to Roy explains why this reasoning is >wrong: there will _not_ be one implementation mechanism, placed in the >origin server, assigning variant-ids for responses of a particular >resource. Such mechanisms can also be present in all proxies in front >of the origin server, because these will want to do preemptive >negotiation on behalf of the origin server. > >If only the server assigned variant-ids, we could allow it to mix the >data of the alternates-part and the variant-part into an opaque token >in an undefined way. But this is not the case. > >>Paul > >Koen. >
Received on Tuesday, 16 April 1996 21:02:42 UTC