Duplicate files, content distribution networks

[Jack Bates <nwv96b@xxxxxxxxxxxxxxxx>]

Are there any resources in Squid core or in the Squid community to help 
cache duplicate files? Squid is very useful for building content 
distribution networks, but how does Squid handle duplicate files from 
content distribution networks when it is used as a forward proxy?

This is important to us because many download sites present users with a 
simple download button that doesn't always send them to the same mirror. 
Some users are redirected to mirrors that are already cached while other 
users are redirected to mirrors that aren't. We use a caching proxy in a 
rural village here in Rwanda to improve internet access, but users often 
can't predict whether a download will take seconds, or hours, which is 
frustrating

How does Squid handle files distributed from mirrors? Do you know of any 
resources concerning forward proxies and download mirrors?