On Tue, Nov 18, 2003 at 12:19:00PM -0500, Barney Wolff wrote: > Some questions, because I'd like to be an educated voter. > > 1. How does multicast routing work now? Presumably something takes a > mcast packet and sends it out to every interface behind which some host > has indicated group membership. Is this kernel or userland? Does it > work at all?
Kernel. Works. Right now, the default multicast route is via the interface with the default route; setting a route isn't necessary unless you need to force multicast to go via a particular interface by default, this is done by longest-prefix matching like all other IPv4 routing activities. Only one copy of the multicast datagram is sent. Running an MROUTER is a special case. The vif mechanism is used to forward multicast datagrams on multiple interfaces under mrouted(8) control. > 2. How is "appropriate" defined - by administrator choice or by some > inherent property of the interface hardware type? For the broadcast case, if IFF_BROADCAST is set on the interface, and it has AF_INET address[es] configured. For the multicast case, a membership must exist for the interface in question. [I haven't written the multicast hack yet, but mdodd@ requested it.] > 3. How do other OS's do it, if at all? Some broadcast on all interfaces, some don't. I'm awaiting more feedback on this, I haven't really researched this point. > 4. How will this interact with IPv6? IPsec? This purely affects IPv4. IPSEC encapsulation gets handled at the ip_output() level afterwards. fenner's objection to this has been noted, he suggests re-architecting my current patch to take place at a higher level. BMS _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
