[10474] in www-talk@info.cern.ch
Re: FW: Mirror Negotiation
daemon@ATHENA.MIT.EDU (Benjamin Franz)
Fri Dec 13 08:39:22 1996
Date: Fri, 13 Dec 1996 05:30:01 -0800 (PST)
From: Benjamin Franz <snowhare@netimages.com>
To: "'www-talk@w3.org'" <www-talk@w3.org>
In-Reply-To: <01BBE88E.B7EAF790@shampoo.res.WPI.EDU>
Resent-From: www-talk@w3.org
On Fri, 13 Dec 1996, Brian Morin wrote:
> Peter Wrote:
> "Isn't mirroring just a special case of caching?"
>
> No, two major differences I can think of (between mirroring and proxy caching.)
>
> 1) Mirrors do not have to worry about keeping data current.
>
> Assuming that updates are sent from the primary site, there no
> need to querry the primary site to determine if data has expired. Given
> that most web transactions involve small files, the cost of opening a
> TCP connection and finding out if data is still current is not trivial.
Incorrect. Mirrors frequently work on a 'pull' model, not 'push', in my
experience. Keeping mirrors current is very much a concern - and it is
not uncommon for a mirror to *fail* to stay current due to things like
mirrors putting everthing on CDROMs on an infrequent schedule.
>
> 2) It gives content providers another tool for improving performance to
> their site(s).
>
> I think that installing more T lines can only do so much.
True. How is this different from proxy caching?
--
Benjamin Franz
