[CentOS] Pause after network initialization

Is there a "proper" way to put in a pause after network initialization to make sure the network *really* is up? I've had this issue for a while with e1000 cards (even on 100MB networks), where the first NFS mount will fail b/c the network reports up but isn't, really. Now, I'm also seeing the same issue on cluster nodes hooked to a switch with jumbo frames enabled.

I used to hack it with a 'sleep 60' at the end of the "start" function in /etc/init.d/network, but that goes away whenever initscripts gets updated. My new hack is to put 'mount -a -t nfs' in /etc/rc.local. Any other suggestions?