Etherchannel Load-Balancing

Unanswered Question
Apr 19th, 2007


I m trying to test etherchannel load-balancing between cat 2950 and 3550 ,

i ve connected two ports from 3550 to two ports of 2950 and configure etherchannel with Lacp protocol ,both links are up and there is connectivity.

Then i pump the traffic to another destination and it sends back the traffic to me now when i check the interface with Show Interface fa0/1 or 0/2 they are not balance sometime there is no traffic on one link and sometimes there is teraffic on both but not balance i mean i want if i pump 2 Mb traffic ,1 Mb goes trough one link and 1 Mb goes trough another one.

Can anyone help me ????


I have this problem too.
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Jon Marshall Thu, 04/19/2007 - 01:38


Attached is a link to an etherchannel load balancing document covering the 2950 and 3550.

Both switches can use either source or destination mac address load balancing. So if you are sending the traffic to the same destination mac-address or sending the traffic from the same source mac-address then you will only use one of the links at a time.



mrmozaffari Thu, 04/19/2007 - 01:49


Thank you for reply.

Can you explain me clearer,i send traffic to a destinaton out of my network here is the diagram:



Jon Marshall Thu, 04/19/2007 - 01:57


The source mac-address will be your client machine.

The destination mac-address (assuming you are routing off the router and not the 3550) will be the router interface that connects to the 3550.

These will not change for the same source/destination.

If you use a different source and you do source mac address load balancing then etherchannel could use a different link.

If you use a different source and you do destination load balancing and the destination is on the other side of the router then etherchannel would use the same link as the source and mac destination have not changed.

Some of the higher end switches can do etherchannel load balancing based on IP address and port numbers which gives you greater flexibility but the 2950 and 3550 don't.



mrmozaffari Thu, 04/19/2007 - 02:15

So please tell me what is the solution when i have a destination on the other side of the Router,the real thing is i use two wireless link in bridge mode between two switches and i want to use the capacity of the both wireless links .

Best Regards Bahman Mozaffari.


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