[openib-general] IPv6oIB neighbour discover broken when MCGs overflow

[Shirley Ma]

Roland Dreier <rdreier at cisco.com> wrote on 02/16/2007 01:55:06 PM:

>  > Two MCGs groups must be establised before IPoIB link up, one is
broadcast
>  > for IPv4, one is all hosts multicast for IPv6. So Node A is a member
of all
>  > hosts address, the patch directs ND sends to all hosts, so node
Aresponses
>  > it.
>
> I'm still confused.  How do you interoperate with other RFC-compliant
> nodes (they might not have your patch or might not even be running
> Linux) that send ND messages to the solicited node group?  If node A
> has your patch and doesn't try to join its own solicited node group,
> then another node that doesn't know to send ND messages to the all
> nodes group will not be able to find it.
>
>  - R.

All nodes in the subnet join all hosts multicast group by default. What the
patch does differently than before, is when join failure, sends to all
hosts multicast group instead of sending to a particular solicited-node
multicast address, the node with the destination solicited-node multicast
address will respond to it, so the network will not lose the connectivity
when MCGs overflow. There is no interoperability issue here between patched
and unpatched node or Linux and none-Linux node. I don't think IPoIB RFC
covers this corner case. So there is no RFC-compliant problem here. I will
discuss this with the author.

Thanks
Shirley Ma
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openfabrics.org/pipermail/general/attachments/20070216/8cc810f2/attachment.html>