Port-Channel Traffic

Unanswered Question
Nov 9th, 2009

Hi All,

I would like to inquire if this design will work and will not cause loop. Server with nic color yellow is a bundle as well as green nic. 3750 is the L3 that holds the SVI and the 2 3560 were trunk going to 3750. Hope to hear your feedback. thanks in advance!

I have this problem too.
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Leo Laohoo Mon, 11/09/2009 - 20:04

I my opinion, if Spanning-Tree Protocol (STP) is enabled then loop is prevented. The worst case that I can see, if the servers are not properly configured, are continuous error logs in the lines of "MAC address flapping between port A and port B".

Mhon Baul Mon, 11/09/2009 - 20:55

Yes your correct, but I see this error before and found out that there is a loop and network goes down. Btw, this server were in vmware and the switchport were configured in trunk. Do you think I will proceed with this design?.

As francisco said. You can probably team the NICs so they appear as one entity but has redundancy built in. The NIC's will establish a keep-alive over the 3750 to transit from one 3560 to the other. But i'll establish a link between the two 3560 and enable spanning tree to prevent outage in case of a link failure from the either of the 3560 to the 3750..


Anyway - you should enable some sort of loop prevention mechanishm. STP, MST, PVST, Rapid-PVST or similar..


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