"Jason" writes:

> I am quite new to linux, but what I am trying to do is to run a
> program between my house and a friend's house that needs a bit more
> bandwidth that my DSL line can provide. I know that I can put in a
> linux router for the DSL line, but is there any application that can
> compress the data before it goes over the DSL line to my friend's
> house?

Several. The question, though, is what is *your* application?
Perhaps it has a compression feature you could turn on without
worrying specifically about the DSL hop. SSH springs to mind; it has
compression features that tend not to be turned on by default. In
practice many applications can be run through SSH, so this applies
also to non-obvious apps like VNC, rdesktop, etc.

Similarly, if one of you is serving http to the other, there is a
compression feature in Apache that, again, is not usually on (or even
present) by default, called "mod_gzip". This makes an enormous
difference, in my experience, to the tune of a 4X-8X capacity
improvement for web servers on the wrong end of a DSL line.

Otherwise, most VPN implementations include, or can include,
compression. So you could look at one of the various VPN
implementations, such as OpenVPN or IPSec. OpenVPN would be
straightforward to implement between two Linux nodes without needing
to change out interim hardware like your DSL router.

On a more theoretical note, the IPComp extension described in RFC 2393
is exactly what you, and probably very many other, DSL subscribers
want. Alas it is not frequently implemented by providers.

--
Grant Taylor
Embedded Linux Consultant
http://www.picante.com/