IGMP report suppression mechanism

Hi,

I have a question regarding to IGMP report suppression mechanism. I
have been reading books about the IGMP report suppression mechanism
but for some reason, I don't see see this actually happening from the
tcpdump output.

On mechine A (192.168.11.11), it's subscribed to 224.3.3.3:

15:47:16.541443 192.168.11.3 > all-systems.mcast.net: igmp query v2
[tos 0xc0] [ttl 1] (id 37003, len 28)
15:47:18.032217 192.168.11.11 > 224.3.3.3: igmp v2 report 224.3.3.3
(DF) [tos 0xc0] [ttl 1] (id 0, len 32, optlen=4 RA)
15:48:16.550648 192.168.11.3 > all-systems.mcast.net: igmp query v2
[tos 0xc0] [ttl 1] (id 37890, len 28)
15:48:18.892217 192.168.11.11 > 224.3.3.3: igmp v2 report 224.3.3.3
(DF) [tos 0xc0] [ttl 1] (id 0, len 32, optlen=4 RA)

At the same time (the clock is a little bit skewed) On mechine B
(192.168.11.22), it has the same client setting:

15:47:34.665191 192.168.11.3 > all-systems.mcast.net: igmp query v2
[tos 0xc0] [ttl 1]
15:47:39.275060 192.168.11.22 > 224.3.3.3: igmp v2 report 224.3.3.3
(DF) [ttl 1]
15:48:34.677361 192.168.11.3 > all-systems.mcast.net: igmp query v2
[tos 0xc0] [ttl 1]
215:48:40.465060 192.168.11.22 > 224.3.3.3: igmp v2 report 224.3.3.3
(DF) [ttl 1]

None of these machines has firewall running and it appears both of
them believe they both need to send out the igmp report with different
delay. I have the same settings extended to 5 machines and I am
seeing the same issue. Is there any reason these boxes didn't see
other people's igmp report and didn't suppress themselves?

Thanks,

--muteki