Re: [squid-users] SQUID @ Satellite Networks using Page Accelerators

Francisco,

I will not say that the RPA apparently does not follow the protocol as it
should (IMS is part of the standard) because that will not help you much.

You can achieve what you want by changing the refresh rules. Use the
override settings to deal with sites that have to strict expire rules (e.g.
expire now)

Marc

At 04:10 PM 9/17/01 -0500, Francisco Ovalle - SMCC SE Mexico wrote:

>I'm trying to setup squid to be used as a Proxy Cache Server for a group of
>computers connected to Internet via a Satellite link.
>
>GLAT (the satellite provider) is using a product called Page Accelerator, who
>runs in two peers. The first one is the RPA (Remote Page Accelerator), this
>piece of SW runs on the remote side and works as a proxy server to the client
>PCs, its main function is to ask the HPA (Hub Page Accelerator, a piece of SW
>running at the HUB or ISP provider) to download an specific Web Page and
>assemble all the pieces (HTML objects such as text, pictures, applets,
>etc), and
>send them all together in a few data streams in order to optimize space
>bandwith
>use (minimizing the quantity of TCP connections that must be opened for each
>HTTP object).
>
>The RPA then receives this few streams and pass them to the client PC.
>
>This RPA SW doesn't do any caching, so here is where SQUID is being used.
>
>The idea is to put the SQUID server between the PCs and the RPA, and make it
>handle all the HTTP requests from the PCs and send them to the RPA, so
>when the
>RPA receive the HTTP traffic from the RPA it can send them over to SQUID
>so it
>can cache the content and accelerate the whole process the next time the same
>page gets requested by any other client PC.
>
>This is working now using the following rules in the squid.conf file:
>
>cache_peer RPA_IP_address parent 9877 0 no-query default
>acl all 0.0.0.0/0.0.0.0
>always_direct deny all
>never_direct allow all
>
>
>So WHAT IS THE PROBLEM ???
>
>The problem arises when the users try to load a page already stored in the
>cache. According to me each time a user's browser try to access a web page
>that
>has been already cached, SQUID connects to the original Web server to
>check if
>the information has recently changed, if it hasn't changed then SQUID
>delivers
>it's own cached copy, if it has changed, then SQUID gets all the new
>information, reassembles the page, caches it and delivers it to the client's
>browser.
>
>The problem is that when SQUID connects to the internet to check if the
>page has
>recently changed, it does it through the RPA (see rules above), the RPA
>doesn't
>have a way to distinguish between this "checking procedure" and a new page
>request, so it brings the whole page again and delivers it to SQUID,
>making all
>the SQUID's caching feature worthless.
>
>So as you can imagine all the connection process when using a SQUID Proxy
>Cache
>is slower than not having SQUID at all!!!
>
>
>THE QUESTION IS ???
>
>How can I tell SQUID not to check for new changes all the time and deliver
>its
>own copy without having to connect to the RPA each time a user asks for a web
>page??
>or
>How can I tell SQUID to check for those new changes directly (not going
>through
>the RPA) and if the pages have changed, retrieve them through the RPA so the
>bandwith gets optimized?
>or
>Any one has any other Idea We could try for this architecture??
>
>
>Thanks and my apologies for the long email.
>
>Francisco
>
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>===========================================================
> ______ ..........................................
> /_____/\ .Ing. Francisco Ovalle F. .
> /_____\\ \ .Consultoria de Sistemas en Ecommerce .
> /_____\ \\ / .Sun Microsystems, México .
> /_____/ \/ / / .Plaza Reforma .
>/_____/ / \//\ .Prol. Paseo de la Reforma No. 600 - 210 .
>\_____\//\ / / .Col. Peña Blanca Santa Fe .
> \_____/ / /\ / .01210, México, D.F. .
> \_____/ \\ \ .Tel. 258-6134 Fax. 258-6199 .
> \_____\ \\ .e-mail: francisco.ovalle@Sun.COM .
> \_____\/ ..........................................
>===========================================================

---------------------------------------------------------
Marc van Selm
NATO C3 Agency, CSD/A

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Received on Tue Sep 18 2001 - 02:15:10 MDT