Subject: Re: Taxonomy Term closure needed

From: Markus Buchhorn <[email-masked]>
Date: Fri, 10 Sep 1999 12:23:38 +1000

At 17:40 9/09/99 -0700, Joe Touch wrote:
>A cache is a system which stores temporary copies of response messages, 
>and replays them when prompted. 

 .. of successful response messages..? or somesuch - not much point caching
error results. And there's also the question of permission/time - being
allowed to cache a response (Pragma: No-Cache; Expires: Now).

>> Reverse Proxy
>
>This is the one I find odd. There is nothing reverse about it.
>It's just a proxy cache co-located (or nearly-colocated) with the server.
>
>Why not just call it a "server-side, or server-proximal" cache?

Agreed. A 'server-side' cache is designed to take load off the origin
server, but does nothing for the network or performance as seen by the
end-user. A 'network' cache is designed to speed up responses for the
end-user and reduce network load.

The term 'Reverse Proxy' to me sounds like a pre-populated caching proxy...

>> Second Derivative Terms: (Build upon first derivative terms)
>> Caching Proxy
>>   A new defintion.  Editors View - Consensus
>>   "A proxy with a cache, acting as server to clients, and
>>    a client to servers"
>
>And which intercepts requests that have associated responses
>in its cache.

No - it "intercepts" _all_ requests, but if it can't service them will
forward them on on behalf of the client, and store the response while also
passing it on. And depending on the application it may not be an
"intercept" (which sounds like a hijack) it may be a deliberate direct
request ("have you got this? If not please get it for me").

>> Replica Origin Server
>>   New definition. Editors View - Open Disussion
>>   Editors-Note:  In light of the recent disuccsion, the authoritative
>>   attribute is quiestionable.
>>   "origin server storing a persistent replica of a data set
>>    stored at the authoritative reference"

How is this different to a mirror ? 

>> Surrogate Cache
>>   Not Defined.  Editors View - Needs Discussion
>>   Editors-Node:  Do we need it, or is it a role that is provided by
proxies,
>>   reverse proxies and replica origin servers?

What does it actually do? If it replaces the role of an existing cache
(dynamically or otherwise) it sounds like a cache-sibling or peer?

Cheers,
	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

---

From: Ian Cooper <[email-masked]>
Date: Fri, 10 Sep 1999 12:35:38 +0100

On Fri, 10 Sep 1999 12:23:38 +1000, Markus Buchhorn wrote:

>error results.

Well, there might be. It would depend on what type of error.

> And there's also the question of permission/time - being

Doesn't that come under the catch-all term "cacheable"?

>end-user.

Not necessarily.  By taking load off the origin server you may well
enhance the performance as seen by the end-user.  I know what you're
saying though.

>request ("have you got this? If not please get it for me").

"Intercepts" seems to hint at the wrong thing (as you say).
"terminates" is probably too strong, although the request stream _is_
being terminated for cached content.

Ian

---

From: Henrik Nordstrom <[email-masked]>
Date: Sat, 11 Sep 1999 14:04:32 +0200

> enhance the performance as seen by the end-user.  I know what you're

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.

--
Henrik Nordstrom

---

From: John Martin <[email-masked]>
Date: Tue, 14 Sep 1999 10:47:30 +0200

>end-user and reduce network load.

"Reverse Proxy" is in common usage and, though I admit I don't particularly 
like the term myself, it is in wide enough circulation as to require 
definition. It is a proxy acting for the server, as opposed to the more 
traditional implementation acting "on behalf of" the client (with or 
without the client's permission or knowledge).

[Off-topic] It does indeed improve the performance as seen by the end user 
if it can quickly serve content from an otherwise overloaded origin server.

As for "'network' cache", please lets not introduce yet-anoth-definition!

> >>   reverse proxies and replica origin servers?

I think we should remove this term and its definition. I have not seen any 
evidence to support that we need it.

Rgds,
John
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