issue 11 -- window size

This issue is about the window size. Mobike needs to be able to
send multiple messages, given that a regular IKEv2 exchange
may be in progress when we suddenly change our IP address.
The question is whether we should expect IKEv2 implementations
to support window size greater than 1, or if Mobike's own
exchanges are in some sense outside the regular IKEv2
window (as proposed in Pasi's MOPO protocol).

The background information we got in the meeting was that
in the IKEv2 bakeoff many implementors did not have
support for larger than 1 window sizes.

So we could either require a larger window size or do MOBIKE
exchanges outside the window. I did not sense a conclusion
in the meeting about this, but on the other hand I'm not sure
if people care about this issue very deeply. For the purpose
of making progress, let me propose one approach. If the
decision was "do it outside the window", would people have
problems with that?

--Jari