[v6ops] Which IPv4aaS mechanisms should CE routers implement first?

[Lorenzo Colitti <[e-mail]>]

Hi all,

Is there any data on what IPv4aaS transition mechanisms are deployed by
ISPs today? I was approached by a router vendor asking me "how they should
provide IPv6-only" and I was looking for data on which mechanisms are most
common.

Official IETF guidance in RFC 8585 and 8026 is "do all of them and let ISPs
decide, have a nice day", but that's not very helpful to a development team
with finite engineering resources and low margins. In particular, it's not
helpful to vendors of routers that are updatable and that can thus credibly
claim that they can deliver other mechanisms via software update. Those
vendors could reasonably argue that it's better for everyone if they launch
the most common mechanism(s) first, and then deliver the others in software
updates.

It seems like reasonable implementation guidance would be to request
OPTION_S46_PRIORITY and parse it, but only initially implement one or two
of the mechanisms and leave the others for a future release. If a router
did this, what mechanisms should it implement first? MAP-E?

Cheers,
Lorenzo