Re: PAgP Learn Method and Port-channel Loadbalancing

The loadsharing on portchannels works with so-called hashes. In your
case for each destination MAC address that is seen outgoing on the
port-channel a hash is generated and divided over 1 of the links
(buckets). So after a while all the possible variations are divided
and are 'shared' on the links. But keep in mind that this is fixed,
traffic to the same destination MAC address is using only 1 of the
links.

Therefore it's highly recommended to use layer 3 and if possible layer
4 information to get the best balancing over the links in the channel.

-- 
Regards,
Rick Mur
CCIE2 #21946 (R&S / Service Provider)
Sr. Support Engineer  IPexpert, Inc.
URL: http://www.IPexpert.com
On 10 nov 2009, at 21:09, Miroslav Kosut wrote:
> Dear group,
>
> a quick question to confirm my understanding. Suppose I configure  
> the following on the same etherchannel:
>
> 1. PAgP learning method to be a "physical-port learning"
> 2. Port-channel loadbalancing to be based on a "destination mac  
> address"
>
> Then, am I right when I am saying that load-balancing method is  
> ignored when a destination mac address is already learned (on a  
> physical-port) ?
>
> My understanding:
> Since the mac is already learned on a physical-port, there is no  
> need to calculate the outgoing member interface (load-balancing).
> Of course, if the mac address hasn't been learned, frames would be  
> unicast-flooded. Then, load balancing IS performed and the outgoing  
> interface is chosen.
>
> Regards,
> Miroslav Kosut
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:http://www.groupstudy.com/ 
> list/CCIELab.html
Blogs and organic groups at http://www.ccie.net