Vlad Yasevich [off-list ref] wrote:
[...]

It doesn't.  What appears to happen in the active-backup case the MLD reports
are not generated on all of the slave devices, just the active one.  Thus the
switch knows only about the active device.

	This behavior is by design.  Previously, it worked the other way
(every slave did IPv6 addrconf stuff, etc), but that confused the
switches because they'd snoop the addrconf traffic whenever a backup
slave came up, and update the switch forwarding table.

When you force the failover, no reports happen because the device believes that
the MLD group was already reported.  Thus there needs to be some trigger after
the failover to tell the switch that the mac address and multicast group have
moved to a different port.

	Yes, there needs to be an ipv6 equivalent of the gratuitous ARP
and IGMP rejoin that's done for ipv4.  I haven't figured out how to
accomplish that yet; suggestions are welcome.

	-J

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com