> We are trying to do exactly what you said won't work - > Getting multicast to > work for a number of Linux Servers running as VM guests using > CTC's back to > TCPIP ... We figured if we could connect a single Linux > server to the an OSA > card (we only have a gigabit card available) we could then > attach all the > servers we wanted in the multicast group via VCTC to it.
Well, it's not that it won't work, it just doesn't work very well; VM TCP doesn't do multicast routing yet, and if you use tunnels to get the traffic past VM TCP, the configuration gets really grotesque. If you want to try to kludge it, you can run mrouted on *all* the servers and build DVMRP tunnels to a central Linux machine, then build a tunnel from the central machine to an outside mrouted (ie, like the early days of the MBONE where nobody knew anything about multicast routing and it was all encapsulation). You could then do mcast on the loopback interface of the applications server machines for the applications to twiddle with. It's not pretty, but it would allow you to do it over CTCs w/o expecting mcast support on the interface. -- db
