Ok quite a simple fix for this one....
The 3Com switches were stopping all the multicast traffic on them. The hosts were joining the session but of course when it started boshing out all the multicast traffic they didnt get it, sat there and timed out.
Went into the switch config and changed IGMP snooping to be disabled and multicasting works a treat. This although does unfortunatly have a downside in that during a multicast task, the whole network gets bombarded with traffic, so it seems. Luckily in this scenario when these tasks will be executed there will be no other users :)
Although I thought IGMP snooping would be able to be enabled for this process to work correctly and only filter out the traffic to the ports relevant to the multicast?
I'm not up to speed on IGMP snooping, but I do know a lot of switches let you organize particular ports into a group with group specific settings for things like multicasting. If these devices are dedicated to those ports on the switch, you might want to look into the documentation of the switch and see if you can enable this type of setting.
It is a layer 3 managed switch and there are a number of options when it comes to this, such as broadcast storms and such like. If I had more time to look into the problem then I might do but for now just having it disabled so far hasn't upset anyone :) Will soon see if it causes any other issues, there shouldn't be any other multicast/broadcast traffic on the network to disrupt normal traffic flow.
Essentially when running multicast traffic/tasks with this setting turned off it denies service to other hosts.
Glad it worked out. Let us know if/how you get the broadcast groups going.
hmmm never had a problem at all with FOG 0.29. Had it in for a month or so now. I didn't set it all up even though it was my idea to implement it, we are currently trying to roll out Win 7 when we get the image finally tested.
We use Nortel 5500 switches.