ndt-users list created

[Jon Kåre Hellan <>]

Jon Kåre Hellan wrote:
> Hi,
>
> I've placed ndt servers at various points in our network, but find that 
> way too many links are reported as 10 Gbps.
>
> Here's part of a web100srv logfile:
>
> Web100srv (ver 3.1.4) process (9461) started Feb 13 14:36:51
> Feb 13 14:36:53  persaunet.uninett.no port 49412
> spds[0] = '  0 0 300 159 2105 5281 53 6 30 7632 0 0 38.68' max=7632 
> [49.03%]

I've looked at the source and found out how NDT estimates link speeds. 
It uses packet pairs, and places speed observations in bins. The bin 
with the most observations wins. In this case it's bin 9, with count 
7632. It represents the range 2500-10000 Mbps.

The interface cards are Intel Gigabit Ethernet - 82547GI according to 
lspci. Could interrupt coalescing be the cause of the strange results? 
May be we are actually measuring bus speed.

Regards

Jon