Interesting Problem: Etherchannel from IBM blade to Cisco 3120X switch

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Feb 13th, 2009
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This is the case. We have a IBM blade chassis with 2 * c3120X switches stacked as normal in blade environment.

Goal is link aggregation from AIX server to blade switches.

We have tried:

802.3ad on AIX side - channel-protocol lacp on switch side and mode active. Result: Port-channel link status "down".

Tried to force etherchannel: AIX server "standard" - Cisco with mode on.

Result: port-channel is up. We got connection. Problem: when shutting a port down that is a member of the channel-group we got ping response from uneven ip address numbers. The other way around, shutting down the other port instead we got ping just from even ip address numbers.

Any suggestions? Please let me know and I will fill in more details if needed.



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owillins Thu, 02/19/2009 - 15:20
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By default, detection is enabled both on CatOS and Cisco IOS Software. It is also possible to monitor the operation of the feature. In order to do this, issue the show spantree statistics mod/port [vlan] command for CatOS. This command show below parameters.

channel_src_mac - Shows the source MAC address of the last BPDU sent or received on the channel

channel src count - Counts the number of BPDUs sent or received with different source MAC addresses

channel OK count - Counts the number of BPDUs sent consecutively with the same MAC address

It show the MAC Address. With the help of MAC address we can easily troubleshoot the IP address issues.

djgeorges Fri, 02/25/2011 - 12:16
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I am in the process of connecting an IBM P770 to a 3750x and creating an port-channel with 4 connections.  Have you discovered the solution to your problem yet?


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