Re: disagreement on which OS should change

[Gyan Mishra <[e-mail]>]

Alex

What real world  problem are we trying to solve with updating the link
local address format.

I don't think a valid reason for updating the standard because of OS
glitches that allow using 1s in the 54 bit all 0s field of the link local
prefix.

I think if we don't have a real world problem  we are trying to solve then
if  nothing is broken why fix something that is not broken.

As you can see it is complicated and there are two methods of making the
change but both options have their complexities and issues.

Option 1:  54 bit all 0s field would be part of the 64 bit EUI station id
so 118 bit field basically a 54 bit extension of the interface is.

Issue with this option I see is that all hosts have the concept of 64 bit
station id EUI64 or random but because of the 64 bit boundary for network
prefix and station id so the 54 bits end up falling in the network prefix
portion of the IPv6 address so then if those bits are set now the hosts
become off net not on the same link local local subnet as other hosts and
all hosts including the router need to have the same exact 54 bits set to
be on now the same subnet.

This option won't work as it really transforms into option #2 with slaac
for link local and dad for link local subnet field

Option #2 link local slaac with DAD algorithm of auto config assignment via
router RA the 54 bit station id.

So for this to work we would have to create a new SLAAC with DAD algorithm
for this new link local subnet field.

For this draft to be viable Option #2 Is the only way I see it possible.

Gyan

Gyan


On Sat, Apr 27, 2019, 1:13 AM Gyan Mishra <[e-mail]> wrote:

> Alex
>
> I agree and that completely makes sense what you are saying.
>
> So with RFC 4291 all hosts for all subnets we’re actually sitting on the
> same fe80::/64 even though different physical or logical interfaces and
> each host was made unique by the EUI64 station id.
>
> So with the new  draft if all hosts would sitting on the same global
> unicast subnet now also sit on the same unique Link local subnet.  So the
> RA for Default route sent to all hosts on the subnet would be this new LInk
> local set on the router
>
> Subnet 1:
> Router A fe80:1::EUI64 bia vrrp vip fe80:1::1  ::/0 sent to host
>
> Router B fe80:1::EUI64 bia vrrp vip fe80:1::1 ::/0 sent to host
>
> Host A fe80:1::EUI64 bia
>
> Host B fe80:1::EUI64 bia
>
>
> Subnet 2:
> Router  A fe80:2::EUI64 bia  vrrp vip fe80:2::1 ::/0 sent to host
>
> Router B fe80:2::EUI64 bia vrrp vip fe80:2::1 ::/0 sent to host
>
> Host A fe80:2::EUI64 bia
>
> Host B fe80:2::EUI64 bia
>
> Gyan
>
> Sent from my iPhone
>
> > On Apr 26, 2019, at 5:11 AM, Alexandre Petrescu <
> [e-mail]> wrote:
> >
> >
> >
> >> Le 25/04/2019 à 18:09, 神明達哉 a écrit :
> >> At Thu, 25 Apr 2019 09:41:35 +0200,
> >> Alexandre Petrescu <[e-mail] <mailto:
> [e-mail]>> wrote:
> >> > >  > That an implementation allows you to do something does not mean
> that
> >> > > it is supported (in the product sense) nor that the RFC is wrong.
> >> > >
> >> > > Right, but I actually don't understand why we still have to have
> this
> >> > > kind of conversation.  Almost all real-world implementations have
> some
> >> > > glitch;
> >> >
> >> > The problem here would be to ask which of the OSs have the glitch: the
> >> > ones that support fe80:1:: or the ones that dont?
> >> Obviously the former.
> >
> > I think it is the latter: the OSs that dont support fe80:1:: should
> change.
> >
> > Alex
> >
> >
> >
> > -------------------------------------------------------------------------
> > If time permits:
> >
> > I would like to make a note here.  I know that AD and Chairs read these
> messages.  I would like to invite consideration of these messages, if time
> permits, when pondering about which way the balance tips.
> >
> > My reading of these discussions is that:
> >
> > - one person, or small group of persons, indeed highly knowledgeable,
> consider fe80:1:: to be a violation of standards, an RFC to be right, one
> OS to be right, manual config of LLs to be wrong.
> >
> > - probably more persons, or at least several persons, consider fe80:1::
> to not be a violation of standards, some other OSs to be right, manual
> config of LLs to be right, 'liberal in what you accept', 'open minded'.
> >
> > (some person is in both categories).
> >
> > This is my reading of the discussion.
> >
> > Alex
> >
> >
> >   The question itself is nonsense to me, equal to
> >> a question asking which OS has the glitch: an implementation allowing
> >> to send a packet with source=::1 outside of the node, or an
> >> implementation that prevents it.
> >> If you don't like to consider it to be a glitch, update RFC4291.  As
> >> you've already seen it would be quite hard, but it's not necessarily
> >> impossible.  Insisting a standard violation behavior is not a glitch
> >> because of the existence of the behavior is just a time wasting
> >> effort.
> >> --
> >> JINMEI, Tatuya
> >
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