Network freezes on Ubuntu Client

Recently upgraded to Ubuntu Studio which I wouldn't think created the following problem but it happened simultaneously.

I have a static IP assigned at boot on Ubuntu 8.04 (upgraded three weeks ago, Ubuntu Studio installed a week ago).

If there is no network activity, the network appears to just freeze. I run a shell and reinit with /etc/init.d/network restart and things instantly begin working again.

I can run ping and keep the network alive, but...

Anyone else have this anomoly? Solutions other than a ping to stayalive?

tx