Hey Noodles, These are a couple of sites that I've found that may help you out:
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This is a great site which I use for anything to do with linux routing (has a great zebra intro as well). Has some really good tips on using tc (traffic control, in the iproute2 package) and a few other random goodies.
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http://www.sonicspike.net/software/ (right at the bottom of page)
This is about limiting on a DSL connection. I havn't tried it myself. Basically, the author created it because wondershaper (coming up next) employs a flawed way of shaping traffic and this software doesnt require kernel patches. Looks interesting though...
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http://lartc.org/wondershaper/
This is a very generic script that basically puts all bulk traffic (i.e. not TCP ACK's, pings, web traffic) into a bulk class, and lets priority traffic (e.g. ACK's, pings and web traffic) traverse the queue and get better responsiveness, even with large downloads. Requires some calibrating. Doesn't quite work for me, For some reason I get _bad_ bandwidth starvation
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http://webs.sinectis.com.ar/lesanti/shaperd/
ShaperD, a daemon that runs in userspace and manages bandwidth shaping. Can do it for masqueraded hosts (NAT) but AFAIK requires another kernel patch (may be included in your distros kernel though). Haven't tested this one either, but looks pretty good.[list]
Hope that helps dude,
Cheers,
Chris.