Re: [v6ops] new draft: draft-chen-v6ops-ipv6-roaming-analysis

[Tore Anderson <[e-mail]>]

> http://tools.ietf.org/html/draft-chen-v6ops-ipv6-roaming-analysis.

Section 4.1 states: "Roaming to IPv4-only networks with IPv6 PDP/PDN
request would fail to get addresses."

In my experience, this is seldom (if ever) the case.

My home network (Network Norway) supports IPv6 PDP context and in
recent years I've roamed in more European countries than I can enumerate
from the top of my head, in some Mid-East countries, in the U.S., and in
Japan. I've made a point out of trying all available PLMNs my phone can
see in the air, and I know for a fact that most of them are IPv4-only.
In spite of this I cannot recall last time I had a problem establishing
IPv6 connectivity when roaming. The way I see it, 3GPP IPv6 roaming is
one of those things that Just Works.

I'm not an expert on 3GPP network architecture, but as far as I've been
able to understand, the reason why this work is that the IPv6 gets
tunnelled back to my home network using GTP, and that the visited
network just considers the payload as "data" and doesn't really care
whether it is IPv4 or IPv6.

I'm sure there could be exceptions to the above. I've heard several
people suggest that Japan is particularly problematic in this regard -
but in my experience it Just Works there, too.

Tore