VMWARE trunk with Cisco Cat6509

[gilson_machado]

Recently I had to establish a trunk port for a VMWARE server (kind of switch). And basically I had to disable spannig-tree (I had to use "set spantree portfast 6/32 enable" command). This command notifies you that loops can happen. I was not able to stop spannig tree for one port only. My concerns is regards to open a door for loops between two SW6509 in a large environement. Question: is there any procedure to implement trunks between VMWARE machines and cisco switches?

Thanks in advance.

[Prashanth Krishnappa]

Enabling portfast does not disable Spanning tree for the entire VLAN but just puts that particular port into forwarding without listening and learning phases. Does your VMWARE server generate BPDUs and does it run STP? Does it have any other connection back into the network other than port 6/32?

If so, I would not enable portfast on port 6/32.

You can trunk if the VMWARE supports trunking as well. 6500 supports ISL(Cisco proprietary) and 802.1Q(IEEE standard) trunking encapsulations.

[gilson_machado]

Thanks for your feedback.

I agree with you on portfast. VMWARE request to disable STP or enable portfast in order to set up a trunk. As per my internal information VMWARE does not generate BPDU and does not run STP.

The VMWARE server has 5 connections 2 trunks into Sw6509-A and 1 trunk into SW6509-B. The SW6509 have etherchannel (trunk-Dot1Q) between them. The other 2 VMWARE ports are normal VLAN for administration only.

VMWARE supports only DOT1Q trunk.

The key is to eliminate the require for portfast.

I wil be searching the VMWARE website for inforamtion.

Do you have any suggestion? It will be very welcome. I do not like configure any "loop situation" for more than 1000 servers and 600 users.