BCMSN Study Question - EtherChannel

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Jul 20th, 2007
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Another BCMSN Study question, how does EtherChannel load ballanace across an uneven number of links? I get the XOR between 2 or 4 links, but what about 3 or 5.

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flashsplash Thu, 07/26/2007 - 23:50
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I don't believe that u can do EC with uneven number. From my knowlegde u used 2 to 8 trunks ports.

bye flash...

It is uneasy question to answer.

Take Catalyst 6500 as an example, Cisco uses its hash algorithm computes a value in the range 0 to 7. With this value as a basis, a particular port in the EtherChannel is chosen. The port setup includes a mask which indicates which values the port accepts for transmission. With the maximum number of ports in a single EtherChannel, which is eight ports, each port accepts only one value. The channel usage depends on the number of ports in the EtherChannel.

So your question

1/ how it works --- see the link from previous replied,

2/ how it works in uneven number -- depend on hash algorithm

3/ XOR -- maybe true to some catalyst model, but not applied to all models.

I really learnt something from your question, thanks!


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