Have you experienced the second nic on a nested ESXi5.1 having no networking connectivity? In my lab I was building out nested vSphere, on a vDS I have nic1 on management and nic2 as the vMotion vmk port. For some reason that nic will not have network connectivity. I built an Ubuntu box and put the nics on the same networks and have no issues, it seems only to be ESXi5.1 with the issue.
For those that want more detail I quickly put together a full write up here: http://grokee.com/nested-esxi5-1-networking-woes/
