Memory depends on configuration. If you need
full routing tables you should have 256MB.
I've quagga running. With two peers it uses 150MB
for bgpd and zebrad alone. So you need some mem
for routingtable, ...
If you just announce your AS and do strong filtering/aggregation
on incoming routes you might find a way to live with 64MB
but it's not worth the work.
So buy a miniitx-Board and throw 512MB on it.
I would use a system of this kind:
http://www.pc-woelfl.de/index.htm?bareb ... _945gm.htm