> From: Robert Elz <[EMAIL PROTECTED]>
> No, you missed the point - the node doesn't send until after it
> has received. It can't receive until someone does ND for one of
> its addresses. To receive the ND packet, it must receive a
> multicast to the solicited node multicast address (if I have the
> correct expression there). That is, multicast has to work before
> packets are transmitted.
The node is listening the solicited node (just has not sent MLD on
it). On a link without this switch, things work fine. With switch, it
would have to recognize the DAD probe.
> | Additional consideration: if solicited-node groups are true part of
> | MLD, then one should note that MLD query with ANY group will elicit
> | responce from almost every node on the link (as I assume high
> | probability that the solicited node groups usually have only one or
> | few hosts each). How many nodes are on the link? Will some reports be
> | lost?
>
> Who cares? Remember these particular packets are only being used, as
> I understand it, for the benefit of the switches. They achieve nothing
> useful at the multicast routing level. As long as your switch sees the
> join (and it is the thing at the other end of the wire from you), then
> it can do the right thing. I'm not sure why anyone would be sending a
> query for one of those, just the join (but the multicast protocols themselves
> are perhaps beyond my understanding, so I might be missing some other
> potential use).
Ahh, but you are missing something: if the switch is booted, you
definitely do not want to require, that EVERY NODE on the link must be
rebooted after the switch.
Before the switch can start applying the collected state, it MUST have
complete state of the active multicast groups on the link. Until it
has complete information, it must pass all multicast groups to the
link.
The *ONLY* way for switch to arrive into complete state after powerup
is to
1) watch for (or generate) a query for ANY multicast group, set a
mark
2) record ALL reports resulting from the query, and new joins
3) when it thinks ALL reports have arrived, it may perhaps assume it
has complete state, and continue maintaining it by watching the
joins.
For the switch to work on link local solicited groups, it MUST rely on
ANY query. Unless, you want to change the ND so that MLD on solicited
nodes must be periodically re-sent by each node?
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