A=1 L=0 PIO

[Templin, Fred L]

Hi Mikael,

> -----Original Message-----
> From: ipv6-ops-bounces+fred.l.templin=boeing.com at lists.cluenet.de [mailto:ipv6-ops-
> bounces+fred.l.templin=boeing.com at lists.cluenet.de] On Behalf Of Mikael Abrahamsson
> Sent: Tuesday, August 16, 2016 4:47 AM
> To: Enno Rey <erey at ernw.de>
> Cc: ipv6-ops at lists.cluenet.de
> Subject: Re: A=1 L=0 PIO
> 
> On Tue, 16 Aug 2016, Enno Rey wrote:
> 
> > from my memory: yes to all of those, for common desktop OS (Win, Linux,
> > Max OS-X). When we did the lab testing for this one
> > (https://www.ernw.de/download/ERNW_Whitepaper_IPv6_RAs_RDNSS_DHCPv6_Conflicting_Parameters.pdf)
> > we played a bit with the L-flag as well, so the L=0 + A=1 scenario
> > occurred. I don't remember any case where the things you mention did not
> > happen. We still have that lab infrastructure so we can repeat (some of)
> > the tests with L=1 (and without DHCPv6). Let me know if you (or the
> > group) is interested; we can assign a student to the task. (I'm on
> > family holiday myself until end of Aug).
> 
> I just tried A=1 L=0 with the following operating systems, all fully
> updated with whatever latest versions is shipping to normal people.
> 
> Windows 10
> MacOS 10.11.6
> iOS 9.3.4
> Android 5.1.1
> Linux 14.04 LTS
> 
> They all did what I consider "the right thing". They autoconfigured
> addresses and used them, and they did DAD on the link.

For a shared prefix (e.g., one that is advertised in a PIO and with
'A'=1),  DAD is required regardless of the state of the 'L' bit.

For a prefix that has been delegated for the node's own exclusive
use (e.g., via DHCPv6 PD), addresses can be assigned to the interface
without need for DAD. This becomes important as the number of
assigned addresses becomes large since it avoids the need for
DAD/MLD multicasts. See: 'draft-templin-v6ops-pdhost'.

Thanks - Fred
fred.l.templin at boeing.com

> --
> Mikael Abrahamsson    email: swmike at swm.pp.se