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Re: FW: Mirror Negotiation

From: Benjamin Franz <snowhare@netimages.com>
Date: Fri, 13 Dec 1996 05:30:01 -0800 (PST)
To: "'www-talk@w3.org'" <www-talk@w3.org>
Message-ID: <Pine.LNX.3.95.961213052338.1554A-100000@ns.viet.net>
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
Received on Friday, 13 December 1996 08:30:33 GMT

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