Understanding Etherchannel

Unanswered Question
Apr 24th, 2007


There is an Etherchannel in in network I am working on between two Cat6509. But for some reason there is no traffic. I am not an Etherchannel specialist. I have read most of Cisco's white papers related to this subject but I still don't really understand the use of it on Distrib layer as the 6500 are at the the distribution layer. Could anybody explain me the way it works ? I also would like to generate some traffic on it but don't really how to proceed.

Thanks in advance.


I have this problem too.
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Amit Singh Tue, 04/24/2007 - 09:18


Are you running hybrid OS or native OS on the 6500.

Ether-channel is primarily used for port aggregation by bundling switchports for bandwidth aggregation.A typical ether-channel configuration is to run an ether-chanel from the access-switches to the distribution switches for bandiwdth aggregation.In your network scenario, your access switches will be uplinked to 6500's with ether-chanel to provide more throughput.

Please see the links below for more understanding of the ether-channel:




-amit singh

deephazz01 Tue, 04/24/2007 - 09:30


I am using IOS 12.2

In fact I have understood the aggregation process. What I don't understand is the L2 links between the 2 cat6500 as it seems there are no uplinks between access switches(3750) and the 6500. I just wonder what kind of traffic(if any) that is not VLAN related could pass through this etherchannel as it is L2.


Amit Singh Tue, 04/24/2007 - 09:36


As you have a L2 etherchannel between the 2 6500 which are primarly used for bandwidth aggregation,the normal vlan traffic will be passed between the switches. If there is not Vlan traffic at this moment, you normal Layer 2 control traffic will still travel across the link like CDP,VTP,STP,Pagp/LACP,DTP.


-amit singh

Edison Ortiz Tue, 04/24/2007 - 09:43

Let's see if your etherchannel is properly configured.

Please post the output from typing

show ether sum

in exec mode.


deephazz01 Tue, 04/24/2007 - 11:27


Well thank you for you answers.

I have removed the etherchannel as there was no traffic on it. I'd rather use features I fully understand ^^. Links are now L3 and added to ospf area.



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