nanog mailing list archives

Re: Android (lack of) support for DHCPv6


From: Ray Soucy <rps () maine edu>
Date: Wed, 10 Jun 2015 09:06:18 -0400

Actually we do support DHCPv6-PD, but Android doesn't even support DHCPv6
let alone PD, so that's the discussion here, isn't it?

As for thinking "long term" and "the future", we need devices to work
within current models of IPv6 to accelerate _adoption_ of IPv6 _today_
before we can get to that future you're talking about.

Not supporting DHCPv6 ultimately holds back adoption, which makes people
see IPv6 as optional for longer, and discourages deployment because vendor
support is all over the place and seen as "not ready".

This isn't theory, we've been _living_ with this as a reality for years
now.  The networks are ready; the clients are not.

Universities see a constant stream of DMCA violation notices that need to
be dealt with and not being able to associate a specific IPv6 address to a
specific user is a big enough liability that the only option is to not use
IPv6.  As I said, Android becomes a second class citizen on the network
under your model.


On Wed, Jun 10, 2015 at 8:21 AM, Lorenzo Colitti <lorenzo () colitti com>
wrote:

On Wed, Jun 10, 2015 at 8:35 PM, Ray Soucy <rps () maine edu> wrote:

In practice, your device will just not be supported.

As you pointed out, there isn't anything that forces adoption of IPv6
right now.


It's certainly a possibility for both sides in this debate to say "my way
or the highway", and wait and see what happens when operators start
removing support for IPv4.


I'm perfectly find NATing Android, and don't see us giving up the
operational benefits to DHCPv6 anytime soon.


Oh, I definitely see that DHCPv6 is easier for network operators.

But even if you're dead set on using DHCPv6, what I don't see is why don't
you support DHCPv6 PD instead of IA_NA? It's the same amount of state. Same
accountability. Same transaction model. But unlike NA, the device gets as
many addresses as it needs. Nothing breaks, and you get future flexibility.
Mobile devices don't have to implement NAT, and application developers
don't have to work around it. You size your IPv6 pools based on the size of
your IPv4 pools, and don't run out of addresses. Technically, that sort of
arrangement is superior to IA_NA in basically every way. So... why use
IA_NA?

Even if the answers are "that's what we do in IPv4, and we want to do it
the same way", or "we're worried that this is strange and will tickle
vendor bugs", "it's not supported by the IPAM we use today", or "this is
what we've decided, our network our rules", I would hope that we as an
industry can think a little longer term than that.

Also, in terms of hotspot functionality being the major driver


Don't think about yesterday, think about tomorrow. Tethering and 464xlat
are just two examples of what can be done when you have the ability to use
more than one IPv6 address and cannot be done without that. We know these
will break today; tomorrow, we can use multiple addresses to do things we
haven't thought of yet.




-- 
Ray Patrick Soucy
Network Engineer
University of Maine System

T: 207-561-3526
F: 207-561-3531

MaineREN, Maine's Research and Education Network
www.maineren.net


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