[v6ops] Apple and IPv6, a few clarifications

[David Schinazi <[e-mail]>]

Hi everyone,

I'd like to clarify a few points about Apple's IPv6 announcements during WWDC 2015.
The video (streaming with Safari or download with all browsers) and slides of that talk
are available at: https://developer.apple.com/videos/wwdc/2015/?id=719 <https://developer.apple.com/videos/wwdc/2015/?id=719>

*) Personal hotspot on iOS
If your iPhone has dual-stack connectivity on its cellular network, the hotspot it creates
will be dual-stack as well. The phone will share its prefix with Wi-Fi clients.

*) Internet Sharing on the Mac
Today, regular internet sharing (from your ethernet to Wi-Fi for example) does not
support IPv6 because of the limited use cases, and the lack of demand for it.

*) Internet Sharing on the Mac - NAT64 testing mode
The NAT64 test mode was designed to help developers ensure that their app can still
function with IPv6-only NAT64+DNS64 connectivity and communicate with their IPv4
server, even if the developer does not have access to the IPv6 internet. That NAT64
network does not have IPv6 connectivity to the global IPv6 internet. As such, the current
version advertises addresses from 2001::/64 instead of ULAs to simulate real IPv6
connectivity, as all IPv6 packets are terminated at the NAT64 server on the Mac.
This implementation detail could change in the future.

*) Making IPv4 literals work on NAT64 networks when using high-level APIs
Starting with this year's versions, if you use NSURLSession to connect to an IPv4
literal on an IPv6-only NAT64-DNS64 network, the API will bump in a IPv6 literal
synthesized using RFC 7050. Note that this will not happen when using sockets
directly. We do not support under-the-sockets bump-in-API (RFC 3338) and we
do not support 464XLAT.

*) Happy Eyeballs
We've heard feedback on our Happy Eyeballs implementation and are investigating
this topic.

Note that this reflects how these technologies work in the current versions of the
2015 betas, many of these details could change in future betas. Please keep in mind
that these betas are previews and we welcome feedback on improving them.

Feel free to contact me if you have any questions, I will also attend IETF93.

Thanks,
David Schinazi
Apple CoreOS Networking Engineer