W3C home > Mailing lists > Public > http-caching-historical@w3.org > February 1996

Re: Proxy notification I-D

From: Balint Nagy Endre <bne@bne.ind.eunet.hu>
Date: Wed, 28 Feb 1996 01:54:57 +0100 (MET)
To: hallam@w3.org
Cc: bne@bne.ind.eunet.hu, http-caching@pa.dec.com
Message-Id: <827.bne@bne.ind.eunet.hu>
Phill Hallam writes [in reply to me]:
> Could you expand upon the problem of dial up users on the end of 
> a phone line? 
Service providers usually don't offer call-out services on phone lines,
consequently the client side proxy can be contacted only when the client
triggers the dial-out process. (X.25 has a 'reverse charge option' on calls, for
X.25 links this isn't a problem. I guess ISDN has a similar feature.)
At least the NOTIFYs should be queued up at the internet side until the proxy
'calls out'.

> I did have a number of thoughts about this case, in particular about
> clients doing aggressive pre-fetch. If I go to the index of the 
> new york times it should start pusshing the front pages down the line at me so 
> thsat the minute I finish one page I can read the next. this means that
> there should be a mechanism for distinguishing real hits from false
> positives.
Essential problem! We should address it!
> I thought I would try a simple proposal as a start then see which extra features
> people thought essential. 
> Perhaps we should regard a proxy cache as being logically a part of the client
> in the dialup case. Maybe we should work on a protocol which allows fast co
> exchange of data with a proxy on the other side of the line. This would be
> the "permanent" representative of the proxy. This server would also be 
> responsible for handling notification operations as well.
Important point. In near future this should be the tipical configuration,
turning the problem into a proxy-to-proxy question. (Currently I don't have
an outer proxy - and I forgot about my (not too attractive) experience
with cascaded CERN proxies in the past.)
Having the outer proxy the problem is significantly easier: the outer proxy
should batch NOTIFYs until the remote proxy forwards a request.
> This is starting to sound like an interesting project, is it really linked to
> the log exchange problem or is it something separate however?
Taking the proxy-to-proxy configuration into account,
the problem seems to me an implementation question with one
exception:  We need a directive telling "I'm a dialup-IP host".

Isn't too ugly to say Proxy-Feature: dialup?

This may solve both questions.

Andrew. (Endre Balint Nagy) <bne@bne.ind.eunet.hu>
Received on Wednesday, 28 February 1996 01:17:23 UTC

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