So quick overview here, I have 4 esx servers 2 still running 3.0.2, 1 clean 3.5 build, and 1 3.5 that was upgraded from 3.0.2. all of these servers are running on an IBM bladecenter with both nics bound to a vSwitch and all other port groups being bound to the vSwitch. The clean build server is having some network issues, in order to make everything work correctly I had to change the Network Failover Detection from Link Status Only to Beacon Probing, while all the other servers are running with link status only and working just fine. Client machines loose network connectivity when being migrated to or being booted from the particular server, it is a hit and miss problem, sometimes it works fine and other times no network. In the instances of no network there is link but no ability to access the rest of the network, a quick fix was to disconnect and reconnect the nic through either vmtools or from the vCenter. The only thoughts I have are bad hardware in the blade, a firmware is required (which I don't know how to check with the blades running), or nic bonding settings on 3.0.2 server carried over with the upgrade and I'm not bonding them correctly on the 3.5 box. Any ideas? If you need logs or some screen shots I'll be more than happy to post them.