I'm also going to pose this question with Cisco but am curious if anyone has tried to configure a Fabric Extender host port as a Trunk in order to connect an ESX 4.1 host to it. I understand that you cannot attach another switch that is reliant upon STP to a Fabric Extender host port because that host port will go into error disable mode as soon as it sees a BPDU. I do not believe that a virtual switch relies on STP and therefore could potentially fall into the below FEX configuration caveat.
When I hook an ESX host up to my FEX host port configured as a trunk, the port does not go into err-disable mode but I cannot connect to any of the trunked VLANs either. The FEX host port shows up/up.
Per the Fabric Extender config documentation from Cisco:
Any edge switch that leverages a link redundancy mechanism not dependent on Spanning Tree such as
Cisco Flexlink or vPC (with BPDUFilter enabled) may be connected to a Fabric Extender host interface.
Since spanning tree is not utilized to eliminate loops, care must be taken to ensure a loop-free topology
below the Fabric Extender host interfaces.
Has anyone else tried this configuration?
