[c-nsp] Preformance proiblems with Nexus5K and 2K 10G to 1G

[Manu Chao]

N5K/N2K are line rate, you needn't to play with fex buffers

TCP Window size use 16 bits: that explain your exact 2^32-1= 65535 max
window size

Iperf: use UDP instead of TCP if you need to avoid any window size wrong
issue


On Sat, Jun 18, 2011 at 3:35 PM, Arne Larsen / Region Nordjylland <
arla at rn.dk> wrote:

> Hi all
>
> Has anyone use iperf for testing performance trough Nexus 5000 and 2000.
> I'm trying to find a problem with EMC nfs-share on 10Gb interace towards
> 1Gb interface.
> If I user iperf as a client on the 10G link and as a server on the 1G link,
> and the only way I can max the link out, is with a window size  of 64K.
> I normally don't have any problems using iperf, and if I do the same test
> on a storeNforward environment.
> I just want to be sure that the result I see is correct.
> And if this is correct, why exact 64K ??. I have tried to tune the buffers
> on the fex, but without any luck.
>
>
> /Arne
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