Linda, The router periodically sends out a general query to which nodes replies to with a report of their multicast listening state. Also, when a node interface is configured with an IPv6 address, the node spontaneously sends a report for the solicited-node multicast address corresponding to the IPv6 address configured.
So routers don't have to know anything ahead of time. And same goes for MLD-snooping switches. --julien On Wed, Nov 21, 2012 at 7:17 AM, Linda Dunbar <linda.dun...@huawei.com> wrote: > Suresh, > > "solicited node multicast address" is formed by taking the low-order 24 bits > of target address (unicast or anycast) and appending those bits to the > prefix FF02:0:0:0:0:1:FF00::/104 > > Routers don't know ahead of time what hosts are present in their Layer 2 > domain. In DC with virtual machines added/deleted consistently, there could > be millions of possibilities. > > What multicast addresses should router send out MLD Query? > > What you are proposing is like using MLD snooping to achieve ND function, > which doesn't scale. > > Linda > >> -----Original Message----- >> From: Suresh Krishnan [mailto:suresh.krish...@ericsson.com] >> Sent: Tuesday, November 20, 2012 5:58 PM >> To: Linda Dunbar >> Cc: int-area@ietf.org; julien.i...@gmail.com; Tal Mizrahi >> Subject: Re: IPv6 ND applicability in draft-nachum-sarp-03 >> >> Hi Linda, >> >> On 11/20/2012 01:05 PM, Linda Dunbar wrote: >> > Suresh, >> > >> > Are you saying that router has to send out MLD Query for all >> potential ND multicast addresses and keep up state for listeners for >> all those multicast addresses? >> >> Nope. Only for those solicited node multicast groups that have at least >> one host on the subnet join. >> >> > >> > There could be millions of "Solicited-Node multicast addresses". That >> is a lot of processing on routers. >> >> Not sure that I follow. Do you have millions of hosts on the subnet? If >> not, I do not see why you have to keep track of "millions of solicited >> node multicast addresses". >> >> Thanks >> Suresh >> > > _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area
