[LINK] ACS new? submission on ISP filtering

[Glen Turner]

The web has very little static content of small sizes suited
to a web cache these days, so there's little advantage in
reduced traffic to ISPs running web caches, transparent or
otherwise.  The savings from the maybe 5% of reduction of
traffic is trumped by the increased helpdesk costs.

ISPs can save significant bandwidth by hosting or peering
with content distribution networks for those huge static
items which do consume a lot of bandwidth.

For the same reasons, ISPs seek to peer with web sites which
generate large amounts of traffic. These peerings reduce
the amount of traffic from transit providers which contain
static items with significant bandwidth cost.

Today I mainly see web proxies implemented in four scenarios:
 - within enterprises for accounting or for security (stripping
   out forbidden items, such as ActiveX code)
 - within school systems for limiting access to content
   (I'll note that these systems usually perform poorly, which
   deeply worries ISPs when people suggest proxies as a suitable
   solution for large-scale Internet filtering.)
 - on the Internet as a device for subverting government-imposed
   Internet filters or for allowing access to IPv4 content from
   non-IPv4 networks.
 - in front of web sites to limit the frequency with which dynamic
   content is computed. This is by far the largest use of proxies
   in the modern Internet.


-- 
 Glen Turner
 www.gdt.id.au/~gdt