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Etherchannel and trunk question


1.)  I'm hoping someone will look at the simple diagram attached to this post.  I want to set this up in our lab to test failover/redundancy would I need to set all the link between switches A, B, C & D as trunks and an etherchannel between A and B as I want to use 4 GB ports and how's ther servers on these cores?

2.)  Would the Etherchannel be a trunk and if so and I guess be part of the STP?

3.)  Is it possible the etherchannel could be shutdown if the STP set this as blocking port?

4.)  I see this sort of network diag all the time if I manually have to see up the bridge id's and root manually would it be normal to make one of the ports on the C or D stack the blocking port?



Re: Etherchannel and trunk question


1) Yes all links between switches must be trunk. As a good practice you must manually set them to trunk.

2) Yes the Etherchannel would also be need to be set in trunk. And it will be the part of STP which will treat the Etherchannel as a single link.

3) Yes it is possible that STP might block the Etherchannel to avoid loops. But you can choose the right switch which should be either A or B as the root bridge and then calculate the STP topology to find out the blocked ports

4) Yes, if you set either Switch A and B as the root then one of the uplinks on Switch C and Switch D will be in blocking.

Please rate helpful posts.

Thanks & Regards

Zeeshan Sanaullah