[ppml] IPv6 addressing plans

Does anyone have any reasoning why a network spanning two or more of the
RIR regions, should or should not get separate ISP allocations from each
region?

I'm not just interested in opinions, but also the reasoning behind them,
especially any technical pros and cons.

In addition, are there any characteristics that define a good IPv6
addressing plan for a network operator?

We've just received an IPv6 /22 from RIPE based solely on projections in
our European network infrastructure. Fairly soon we will have to decide
whether to internally assign chunks of that space to our North American
network or to go to ARIN for a separate IPv6 allocation based on North
American needs only.

I imagine that a number of other companies are in this position and if
there is actually a best practice for IPv6 addressing, it would be good
to document it and follow it before deployment gets much further ahead.
On the other hand, if it is a coin-toss scenario from a technical point
of view, it would be nice to see general acknowledgement of that fact.

--Michael Dillon