[dhcwg] Re: [v6ops] Re: [IPv6]Re: Android now su pports DHCPv6 PD

Hi,

On Tue, 16 Sept 2025 at 19:05, Lorenzo Colitti <lorenzo=
[email protected]> wrote:

> Recommendations for network operators are written in RFC 9663. Some text
> about expected prefix lengths is in section 8 of that RFC. RFC 9762 says
> the prefix must be SLAAC-sized, which currently means it must be a /64 per
> device. A /48 is fine for a small or medium network, but a campus with tens
> of thousands of devices on it probably needs more than that.
>

I would assume (and I'm interested to find out otherwise) that once a
network gets to say 30K hosts, then they've moved to BGP as their main
routing protocol. 65 536 /64 routes in BGP is a walk in the park, so a /48
for a network of say 50K hosts each with is own /64 and 15K /64s left over
for everything else would seem to be a large network. In other words, I
think a /48 would suit all but the largest networks.

Are there large enterprise or university networks with 10s of 1000s of
hosts that aren't using BGP (yet?).

Regards,
Mark.


>
> On Tue, Sep 16, 2025 at 5:59 PM Tim Chown <Tim.Chown=
> [email protected]> wrote:
>
>> Hi,
>>
>>
>>
>> Good news, thanks.
>>
>>
>>
>> What’s the recommended deployment model for PD to the host in a campus
>> WiFi scenario?   I can certainly see advantages for it, as you’ve
>> highlighted in your email.  The linked article explains “what this means
>> for app developers” but a “what this means for enterprise/campus network
>> operators” would be useful.
>>
>>
>>
>> Is it a given that in a middling or large campus the operator will need
>> to now receive more than a /48 from their NREN?  Or was that always too
>> cautious?  A small but growing number here are obtaining LIR status
>> directly.
>>
>>
>>
>> Tim
>>
>>
>>
>> On 16/09/2025, 09:49, "Lorenzo Colitti" <lorenzo=
>> [email protected]> wrote:
>>
>>
>>
>> There was a typo in the original post. It was fixed earlier today; it now
>> says "Android 11 and above"
>>
>>
>>
>> On Tue, Sep 16, 2025 at 3:21 PM Maciej Żenczykowski <maze=
>> [email protected]> wrote:
>>
>> There's a reddit thread:
>>
>>
>> https://www.reddit.com/r/Android/comments/1nhzsst/android_developers_blog_simplifying_advanced/
>>
>> First comment:
>>
>> There's a mistake in the page: running Android and above before the
>> end of the year via a Google Play System Update.
>>
>> Which version?
>>
>>
>> On Tue, Sep 16, 2025 at 3:59 AM Stan Barber <[email protected]> wrote:
>> >
>> > Congrats!
>> >
>> > On Mon, Sep 15, 2025 at 6:32 PM Lorenzo Colitti <lorenzo=
>> [email protected]> wrote:
>> >>
>> >> FYI, we announced DHCPv6 PD support on Android today:
>> >>
>> >>
>> https://android-developers.googleblog.com/2025/09/simplifying-advanced-networking-with.html
>> >>
>> >> This change should already be live on most Android devices running
>> Android 11 and above. Specifically:
>> >>
>> >> RFC 9762: if the P flag is set, the device will ask for a SLAAC-sized
>> prefix, and if it gets it, use it to form addresses. Some devices will also
>> disable SLAAC as per the SHOULD in the RFC. Not all devices will support
>> this because it requires a kernel change which will be rolling out over the
>> coming months. In future releases, we expect that the prefix will be shared
>> with downstream devices, wearable devices, VMs, etc.
>> >> Heuristic: if the device obtains a default route but not PIO, it will
>> ask for a prefix, and if it gets it, use it to form addresses. This allows
>> DHCPv6-only networks to support Android devices today without having to
>> upgrade their routers to set the P flag.
>> >>
>> >> Over the next few months we also plan to roll out support for DHCPv6
>> address registration (RFC 9686).
>> >>
>> >> I would like to thank everyone who contributed to RFC 9663, RFC 9762
>> and RFC 9686. We think that DHCPv6 PD is *better* than either SLAAC or
>> IA_NA, because it allows the device to provide end-to-end connectivity to
>> unlimited devices, containers, VMs etc. without scaling load on the
>> network. Plus the prefix can be tracked and managed by the operator, which
>> means that it should be possible to deploy it in networks that require
>> DHCPv6 or that have scaling issues dealing with many addresses. We hope
>> that this will allow at least some enterprise operators to deploy IPv6 to
>> Android devices.
>> >>
>> >> Cheers,
>> >> Lorenzo
>> >> _______________________________________________
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>> >
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>> > --------------------------------------------------------------------
>>
>> --
>> Maciej Żenczykowski, Kernel Networking Developer @ Google
>>
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