Dummynet for multicast traffic on FreeBSD 6.0-Release

[Wang, Xi (GE, Research)]

Hi, 

I am using ipfw to introduce end-to-end delays for multicast NORM traffic on 
FreeBSD 6.0-RELEASE box on which mrouted is running.

Without any ipfw rules, I was able to send and receive multicast traffic from
sender and receivers. I was able to observe the multicast information through
"netstat -g" on the FreeBSD box. However, when I introduced the following rules,
I was not able to establish multicast sessions and no receivers can receive
any packets from the sender.

# sender
ipfw add pipe 1 ip from 10.0.1.1 to 232.0.0.10 out

# receivers
ipfw add pipe 2 ip from 10.0.2.2 to 232.0.0.10 out
ipfw add pipe 3 ip from 10.0.3.3 to 232.0.0.10 out
ipfw add pipe 4 ip from 10.0.4.4 to 232.0.0.10 out

ipfw pipe 1 config delay 100ms
ipfw pipe 2 config delay 100ms
ipfw pipe 3 config delay 100ms
ipfw pipe 4 config delay 100ms

I verified through "ipfw show" that the rules are active. To be sure that ipfw is
actually working, I setup a rule that introduce end-to-end delay between 
10.0.1.1 and 10.0.2.2 and it worked just fine.

Does anyone know how to set up ipfw rules to introduce delay between sender
and receivers for multicast sessions? Any suggestion is greatly appreciated.

Thanks,

-Xi