Hi, Wes, You could probably coax the current 10 GbE block to do multicast. Since the 10 GbE block assumes that all locally connected devices (i.e. on the same subnet) have the same the first 24 bits of the IP address as the core's own IP address. So you could choose a block of 256 consecutive multicast addresses and assign the core's IP address in there and then you could send to 255 other multicast groups. You'd have to manually populate the ARP tables since multicast IP packets must be sent in Ethernet packets with a multicast MACs. This "trick" would mean that the core would only send multicast packets and would not be able to send unicast packets.
Ideally, the 10 GbE block would be modified to recognize multicast destination IP addressed and then add in the derived MAC address automatically instead of getting it from the ARP table. Then it could send both multicast and unicast packets. It would be another matter to get the core to listen to multicast packets (especially multiple multicast groups). I think that would be a little more complicated (unless you set its IP address to a single multicast IP and that's the only multicast group you want it to join). Hope this helps, Dave On Sep 19, 2013, at 1:45 AM, Wesley New wrote: > Hi all, > > I am looking at implementing multicasting on the Ten Gig Ethernet cores for > ROACH. Has anyone looked at doing this before or even implemented it and not > committed it to the CASPER repo? Any comments and suggestions would be > welcome. > > Thanks > > Wes > > > Wesley New > South African SKA Project > +2721 506 7365 > www.ska.ac.za > >
