5G roadblock: labor

Fri Jan 3 22:27:17 UTC 2020

On Fri, Jan 3, 2020 at 2:17 PM William Herrin <bill at herrin.us> wrote:

> On Fri, Jan 3, 2020 at 2:11 PM Ca By <cb.list6 at gmail.com> wrote:
> > You are not using ipv4 today.
> >
> > The scenario you describe, using facetime (iOS) on T-Mobile US, you are
> not using ipv4 on the device.  T-Mobile does not assign ipv4 addresses to
> iOS or Android devices in default scenarios, has not for years.
> >
> > If the far end of your facetime call is v4-only, you may need nat64 in
> the cloud.... but otherwise no v4 in the flow, and no v4 on the device.
>
> AFAIK, that's not correct. T-Mobile does provide IPv4 *on the device*
> but translates it to IPv6 (464xlat) before the packets leave the
> device for the network.
>
> Regards,
> Bill Herrin

Eh. True. Semantics, to a degree.

T-Mobile does not assign an ipv4 address to the handset. That said,
T-Mobile assigns a v6 to the handset, the handset then does 464xlat as you
said, assigning itself a special v4 address to v4->v6 nat on handset.

And, Bob is your uncle, as they say.

>
> --
> William Herrin
> bill at herrin.us
> https://bill.herrin.us/
>
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