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Re: [LUG] Compress GPRS through server

 

Simon Williams wrote:
> 
> Any ideas?

The "obvious" way of doing this with HTTP in the general case of a slow
link is via a proxy. Tunnelling tends to be a mixed bag, because tunnels
have overheads.

Proxies can reduce round-trips, and shift some of those round-trips
(i.e. DNS) off the slow link, and onto the servers link (which we assume
is a good link otherwise the proxy server need relocating.

The bad news is that Transfer-Encoding (or more properly
transfer-coding) isn't there in Squid. This is the technology that
RFC2616 defines, to allow a proxy to compress data if the HTTP server
didn't, but the browser can handle it.

There are patches around for some versions of 2.x, and in theory Squid 3
should make it all better (eventually), but Squid development is slower
than almost any project except GNU Chess :(

In the meantime persuade everyone to install the Apache deflate module
(or equivalent) as a workaround :(

http://www.debian-administration.org/articles/137

Still you might like to time with/without a well placed proxy, although
I assume if the mobile operators have any sense they are proxying
traffic anyway?!

Worth also defining if you want to minimize bandwidth (i.e. cost), or
minimize latency (i.e. delay), whilst they are usually the same thing,
sometimes you can reduce latency using techniques that don't reduce
bandwidth, and vice versa.

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