RE: 3gpp-analysis-04: Transition mechanisms at UEs; 3GPP IPv6 deployment

["Christian Huitema" <huitema@windows.microsoft.com>]

> If UE that normally uses IPv6 roams to a provider that only supports
> IPv4, some kind of tunnel solution seems inevitable. ISATAP is
> certainly irrelevant, because the IPv4 provider won't provide
> ISATAP machinery by definition. So either the home provider will
> have to offer a tunnel broker or a 6to4 relay for use by its
> subscribers when they roam on IPv4. I don't think the IETF
> should worry about whether the UE has enough real estate for
> this option; that's a vendor choice.

An UE can only use 6to4 if the ISP provides it with a global IPv4
address. I suspect that the same 3G ISP that are looking at not
providing IPv6 support are also looking at not providing global IPv4
addresses. There are certainly many GPRS service today that by default
provide you with net 10 addresses; you have to pay extra to get the
"professional" option and a global address.

If the ISP does not provide a global address to the UE, then IPv6
connectivity can only be obtained via a tunneling protocol that goes
through the ISP's NAT -- either some form of VPN or tunnel, or a Teredo,
or a variation of these.

--Christian Huitema