All things related to multicast

[Dave Hartzell <>]

Hello-

I've been testing IPerf (v1.1.1) in multicast mode and I seem to be 
running into a limit of 11 mbit/s when sending or receiving a multicast 
stream.

I'm using two BSDI 4.2 boxes with 3C905 cards connected to the same 
Cisco 2900 XL switch.

On one box, I source a stream and on the second box I'm receiving that 
stream, using the following commands:

On the 'source':

iperf -w63K  -c 236.1.1.2 -u -T 1 -t 10 -i 1  -t 30 -p10000 -b 10M

On the 'receiver':

iperf -s -u -B 236.1.1.2 -i1  -p10000

I've had to mess with the window '-w' option on the source side, and 
that does help, but I don't seem to be able to go beyond 64k for the 
window size.

The Cisco Cat 2900 XL switch in the middle is running an older version 
of IOS, 11.2(8)SA1.  This probably needs to be upgraded.

Can anyone tell me what (or if) the bottlenck is here?  Perhaps I 
shouldn't expect too much more, but I would think that 11 megabit/s and 
greater should be achievable.

Thanks!

Dave Hartzell