Subject: Re: Taxonomy Term closure needed

From: Markus Buchhorn <[email-masked]>
Date: Wed, 15 Sep 1999 14:17:55 +1000

At 14:04 11/09/99 +0200, Henrik Nordstrom wrote:
>
>Also, technically the 'server-side' cache (accelerator) does not need to
>be co-located with the actual server. It may be located in another
>continent, and have different network connectivity to the origin server
>than the end user. So it may both enhance the performance and take load
>off the network depending how it is deployed.

So how is this thing different to a 'mirror' or 'replica' ? It seems to
come back to 'management' and 'intent' which Joe doesn't like as they're
'unobjective' as a metric. Terms like 'server-side' and 'client-side' imply
some line that you can be on one 'side' of. When dealing with multiple hops
along the way (e.g. cache-to-cache) you may be 'client-side' of one side
and 'server-side' of the other, and it rapidly becomes a tangled mess. 

It seems like server-side and client-side are only differentiated by their
relationship with the origin server (or other server? :-( ), and their
relationship with the end-user/client is irrelevant?

Markus

Markus Buchhorn,  Advanced Computational Systems CRC     | Ph: +61 2 62798810
email: [email-masked], snail: ACSys, RSISE Bldg,|Fax: +61 2 62798602
Australian National University, Canberra 0200, Australia |Mobile: 0417 281429

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From: Patrick McManus <[email-masked]>
Date: Wed, 15 Sep 1999 08:39:35 -0400 (EDT)

In a previous episode Markus Buchhorn said...
:: 
:: At 14:04 11/09/99 +0200, Henrik Nordstrom wrote:
:: >
:: >Also, technically the 'server-side' cache (accelerator) does not need to
:: >be co-located with the actual server. It may be located in another
:: >continent, and have different network connectivity to the origin server
:: >than the end user. So it may both enhance the performance and take load
:: >off the network depending how it is deployed.
:: 
:: So how is this thing different to a 'mirror' or 'replica' ?

   1] mirrors/replicas are complete and never self
   updating.. essentially a special case of the surrogate
   administrative policy

   2] intent

   3] the authoritative data is part of the surrogate in some way.. at
   least by my definition that views the surrogate proxy and the
   traditional HTTP server clustered together as the origin server

:: It seems to
:: come back to 'management' and 'intent' which Joe doesn't like as they're
:: 'unobjective' as a metric.

maybe this needs to be rethought? The taxonomy isn't a protocol
document specifying interoperability, instead it "specifies standard
terminology and the current taxonomy of web replication and caching
infrastructure deployed today. It introduces standard concepts and
protocols usesd today within this application domain"..

concepts can clearly include intent as part of their composition
without providing criteria to evaluate individual deployments against
intent.. to borrow from US Law, several statues require intent as an
element of the crime (1st degree murder for example) while not
providing evaluation criteria for it.. the viewer has to discern from
the circumstances whether or not it fits.. 

if we call surrogates/mirrors/replicas all the same thing we haven't
fufilled our objective of providing "the current taxonomy of
[wrec]". The technical difference between them does seem to be

	 1] intent
	 2] administrative policy

-P