Re: DAST: Iperf - multicast with iperf - Tom.Gorman --at-- draeger.com

[debbie fligor <fligor --at-- uiuc.edu>]

Tom,
You didn't say what version of iPerf you were using 2.0.1 had a known 
multicast bug that no matter what the TTL setting was specified, it 
was always "1", so it wouldn't work through even one router (it 
should have worked if your two test stations were on the same LAN 
though).

I've not tested 2.0.2, but I know 1.7.0 works well with multicast, 
I've personally used it for testing, and we've also used it in the I2 
multicast workshop labs.

when doing multicast testing across routers, be sure you set -T 
(multicast TTL) to something larger than the number of routers in 
your network  -T32 or -T64 generally is plenty.

Unfortunately I don't use iPerf on windows, so if you are using 1.7.0 
or 2.0.2 I can't really help you debug your problem, but perhaps 
someone else can.

At 16:50 -0600 11/1/05, Mitch Kutzko wrote:
>  >Date: Tue, 1 Nov 2005 16:37:44 -0600
>  >To: Tom.Gorman --at-- draeger.com
> > Subject: DAST: Iperf - multicast with iperf - Tom.Gorman --at-- draeger.com
> >
> >
> > Contacting DAST re: Request for information about Iperf
> > From: Tom Gorman <Tom.Gorman --at-- draeger.com>
> >
> > Subject: multicast with iperf
> >
> > Question/Comment:
> > We at Draeger Medical make patient monitoring systems which use multicast
> for more than 90% of our traffic.  The iperf tool seems suited to help with
> testing, but at least on Windows 2000 the display does not correspond to
> the documentation.  We never see "Joining multicast group" and a transfer
> is always followed by ICMP message "destination unreachable".  A dump of
> the packet shows the destination port is the issue.  The -i and -b switches
> function as advertised.  We'd love to know if we are doing something wrong.
>  Ethereal traces confirm the transfers.
> > How significant are the values following the -l switch? If the server
> receives packets of a size different from what it expects, does it ignore
> the packet? Our monitors can transmit packets of various sizes.
> > Thank you very much.
> --
> Mitch Kutzko | mitch --at-- dast.nlanr.net | mitch --at-- ncsa.uiuc.edu | 217-333-1199
> Project: http://dast.nlanr.net  |  Personal: http://hobbes.ncsa.uiuc.edu


--

-debbie
Debbie Fligor, n9dn       Network Engineer, CITES, Univ. of Il
email: fligor --at-- uiuc.edu          <http://www.uiuc.edu/ph/www/fligor>
"Every keystroke can be monitored. And the computers never forget."