Note that there is a pretty nasty regression in kernel 2.6.32-279.1.1 if
you're using bonded network connections with quad port broadcom nics

See https://bugzilla.redhat.com/show_bug.cgi?id=834764

It shuts the network off completely. 

Hopefully it'll get sorted shortly, but in the meantime beware if you
have these cards and make sure your console access is working...