[nsp] Frame distribution on catalyst channel

[Nipper, Arnold]

The answer is that you only get even distribution if you the # of channels
in the bundle is 2^n (n=1,2,3). Otherwise distribution might look like

For 3 port channel the load balancing would be 3:3:2
For 5 port channel the load balancing would be 2:2:2:1:1
For 6 port channel the load balancing would be 2:2:1:1:1:1
For 7 port channel the load balancing would be 2:1:1:1:1:1:1

This is due to the hash algorithm which gives a value between 0 and 7.


Arnold


On Wednesday, November 19, 2003 1:40 PM, Nipper, Arnold <arnold at nipper.de>
wrote:
> We ran a 4 GE channel (ip both) between two Catalysts 6509 (CatOS 7.2(2)).
> Distribution of frames were almost equal. Now we buildt another 5GE
channel
> and switched all traffic to the new channel. But now distribution is not
> longer equal but looks like 2,2,2,1,1. I.e
>
> sw001> (enable) sh channel traffic
> ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
> ------ ----- ------- ------- ------- ------- ------- -------
>    840  7/15  25.08%  17.57%  17.72%  44.63%  21.54%  21.50%
>    840  7/16  24.75%  15.54%  14.20%  27.31%  45.11%  16.99%
>    840  8/9   25.26%  51.05%  28.58%  12.95%  17.39%   6.43%
>    840  8/16  12.53%   8.08%  14.20%   8.74%   7.71%  42.26%
>    840  9/15  12.36%   7.74%  25.28%   6.35%   8.23%  12.79%
>
> There are 100+ routers connected to both switches with a lot of IP
addresses
> behind each router so that (ip both) should almost distribute even.
>
>
> Arnold
>
>
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