Want to have cache server for small ISP

[Darshak Modi]

Hello,

I want to deploy a cache server for small ISP.
 From documents , I understand Varnish can be used for reverse-proxy only.

I have to cache all world HTTP traffic, video traffic, updates for end 
client who are using ISP internet.
Cache server to be deployed at ISP router end.  I gone through Squid and 
I think it can work.

But I can not understand if Varnish can be used for the same purpose.?

Please guide.