Can you trunk two ports on two different switches in the same StackWise stack?

[leam_hall]

Morning all!

We're looking to add some redundancy for a few of our larger hosts and I'd like to trunk two ports for one of our devices. The question is, if I have a StackWise connected pair of 3750's, can I trunk one port in Switch A with one port in Switch B?

Thanks!

Leam

[Collin Clark · Accepted solution]

Leam-

Yes you can do that but there is a caveat. Some or all of the ports for the VLANs will go into blocking. You will be creating a spanning tree loop and to prevent broadcast storms, the switches will place one (or more) ports in blocking mode to prevent the loop. It could happen in your stack or other switches that the VLAN is on. To prevent this you can create a L2 etherchannel between your two switches and have it trunk.

[hegegabor · Accepted solution]

Hi,

In the cisco phrase the trunk means 802.1Q.

the trunking that you want is the etherchannel.

And the answer is yes you can "trunk" aggregate links with etherchannel on different devices.

here you can find a config example:

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00806cb982.shtml

vote if it helps.

regards

Gabor