Proxy Mobile IPv6 (PMIPv6) Multicast Handover Optimization by the Subscription Information Acquisition through the LMA (SIAL)
draft-ietf-multimob-handover-optimization-07

I understand there are two implementations in the works, and an interop test planned.  That satisfies my concern, my DISCUSS is cleared, and I hope the experiment is a raging success.  Thanks.

Thanks for adding some text to address the sequence number. 

Happy New Year!

Are you missing a (minor) security consideration?  The new
subscription query message does expose a little more
information to the LMA when the MN roams from the pMAG,
that is, the set of MC groups to which the MN is
subscribed. If the MN took the hit of a delay then I guess
only the pMAG and nMAG would know about the current MC
groups and the LMA might not.  If that's correct, then a
nasty LMA could use that to track the MC groups to which a
MN subscribes. I think that's perhaps worth noting, but am
not suggesting you do more than that.

Former DISCUSS, which I have cleared:

How does the LMA decide whether to follow the procedure illustrated by Figure 3 rather than the procedure illustrated by Figure 4?   Why not always follow the procedure shown in Figure 4?

This seems like kind of a big deal, since any buffering of TCP flows will result in unfortunate behavior on the part of TCP congestion-avoidance.   Indeed, why not do the procedure described in Figure 4 but without any PBA Timer—just send the PBA immediately and handle the multicast updates with a Subscr Query/Subscr Resp exchange in the reactive handover case?   I realize that this adds latency in theory, but in practice I would expect the request going to the pMAG to get a response in the same rough timeframe as the query coming back from the nMAG, meaning that in practice the Subscr Resp from the LMA to the nMAG would go out at roughly the same time that the delayed PBA would have.