[v6ops] I-D Action: draft-ietf-v6ops-ipv6-roaming-analysis-02.txt

[Tore Anderson <[e-mail]>]

(Changing the subject like Ross did.)

* Mikael Abrahamsson

> I've heard reports of platforms in use in southeast asia, I don't
> remember if it was Korea or some other country, would fail when
> presented with IPv4v6 capability.
> 
> The reason why people are not going for IPv4v6 externally is because it
> breaks things, badly, it seems, due to bugs. So this is why IPv6 only
> bearer is so appealing, because it's been around for 5-10 years and very
> few things break with it.

Yep, and to be clear, Telenor Norway does not support the IPv4v6 on
their IPv6-capable APN (nor does Tele2/Network Norway). Furthermore,
Telenor only supports IPv6 (not IPv4), while Tele2/NwN supports both
IPv6 and IPv4.

Which leads me to a point I forgot to mention before, if Telenor had
used Roaming Protocol = IPv4 as Ross suggested, or if the phone RIL did
a similar fallback, it would actually ascertain failure, since the APN
doesn't allow IPv4. If IPv6 fails, one would have to change to one of
the IPv4-only APNs.

> The scary part isn't enabling IPv6, it's enabling IPv4v6 or capability
> to do so. When advertised as capability to visiting SGSN it might refuse
> to bring up any bearer at all. So this is why the draft suggests it
> might be a good idea to not advertise this to roaming partners.

Yes, the -02 draft makes it much clearer than previous versions that
this concern is applicable specifically for IPv4v6 and not for IPv6.

In spite of this I see that some providers that are using IPv6 and home
routing chose to set the Roaming Protocol to IPv4. This is what I don't
quite understand the reason for. Perhaps due to a misunderstanding that
the problems IPv4v6 also apply for IPv6, or some other problem I have
yet to come across?

I don't really know much about what's going on "under the hood" in
mobile networks to be honest, but with my "dumb user" hat on I can
conclude that IPv6 roaming seems to work just fine with the way Telenor
and Tele2/NwN have implemented it. So I'm happy. :-)

Tore