... when I can;t communicate with the SC.
That's a valid point, sorry I missed this Image may be NSFW.
Clik here to view.
IMO there's an issue with the VLAN/port configuration. Either the native VLAN matches the VLAN configured for the SC port group or there's an issue with the port configuration on the physical switch (see e.g. http://kb.vmware.com/kb/1004074)
André
