Re: Asymmetrical bandwidth

Steven Kurylo wrote:
>> So regardless of which machine I test from, I get about 90 Mb/s in either
>> direction.
>> But in dual mode, the data leaving the linux box is 90 Mb/s, and coming in
>> is 20 Mb/s.
>
> Its been a long time since I used iperf, but that doesn't make sense.

If you have a recommendation for something else, I'm open to it.

> They should eventually normalize to the same speed. Try running two
> instances of iperf in either direction, instead of one doing both.

Running two instances of iperf, one in each direction, simultaneously,
the linux box sends to XP at 90 Mb/s, and the XP box sends to linux at
22 Mb/s.

So then I tried from a third computer, a laptop running XP, in dual mode.
 From the notebook to the original XP: Out 61 Mb/s, In 86 Mb/s
 From the notebook to the linux box: Out 20 Mb/s, In 92 Mb/s
So between the XP's, only a slight difference.
But when talking to the linux box, same results as before.

> What does a udp test show? Is the cpu being maxed out?

UDP to the linux box is about 25, when it's just a simple test, and the
same if I run a UDP test from both machines simultaneously. The UDP from
the linux box to the XP box is about 86. In UDP dual mode, same results
(86 and 25)

No, cpu load is low, about 5%, so I think it shouldn't be relevant.

> What kind of switch? Try without it?

The switch is the one built into the Linksys WRT54G, which is running
DD-WRT. Given my other tests between the XP boxes on the same switch,
I'm not suspecting the switch.

      Les...
Received on Sun Jun 1 20:12:24 2008