freebsd realtime network usage limiter?

[deeptech71 at gmail.com]

That is, I have a router connecting to the internet through PPP. There are 4 
computers (and a DSL modem) connected to the router. The router does not limit 
or share internet speed evenly, so if I download via TCP at full speed, others 
complain about slow loading web pages. My comp has a FreeBSD OS. How can I 
limit my upload and download speed to, say, 0.333 of the speed permitted by my 
provider? Also, if I had a FreeBSD router, how could I share speed evenly?

BTW: Is it true that are some types of traffic that need higher priority, such 
as games using UDP, so that data does not lag?