Umm... that's a RADIUS server. Well, at least you spelled my name correctly.
Not dedicated. It can be used for other things at the same time. Think multitasking. There's very very very little traffic involved in the use of a RADIUS server. However, it does have to be powered on and running in order to be useful.
If you want to test your system, you might want to download the latest Kali DVD (2.6GB) and boot it on a random laptop. The major penetration testing, password cracking, and network sniffing tools are there, ready to run.