Subject: RE: Textual Address Change for Scope-IDs

From: Brian Zill <[email-masked]>
Date: Sun, 21 Nov 1999 01:46:33 -0800

Sam Manthorpe wrote:
>
> Brian Zill wrote:
> > At the risk of repeating myself a billion times,
> > the same issue exists for link-local addresses.
> > Getting rid of site-local addresses would not
> > make this issue go away.
> 
> Yes, but multiple ND on each interface for link-locals,
> although _theoretically_ flawed would work in practice.

I suspect you're just playing devil's advocate, but:

I think it's more than theoretical, point-to-point links and tunnels often
have small integer numbers as their interface identifiers.  Multiple ND has
its problems and is non-trivial to implement.

Besides, I don't _want_ to throw away site-local addresses, and I suspect
most of the others on this list don't either.  Especially not just because
the API is broken (and easily fixed).  I'll point out that site-local
addresses are part of an IETF standards document, whereas the API is just an
informational document that one doesn't have to follow to be IPv6 standards
complaint.  Discussing changing the protocol just to make the API discussion
go a little easier strikes me as bizarre at best.

--Brian
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From: [email-masked] (Sam Manthorpe)
Date: Sun, 21 Nov 1999 02:27:44 -0800 (PST)

Hi Brian,

Brian Zill wrote:
> have small integer numbers as their interface identifiers.  

Either there's a misunderstanding or I missed something.  I'm
thinking: ping <site-local-addr>.  The kernel doesn't know what
interface to use so it does ND on all of them.  The first reply
it gets wins.  I don't get the connection with interface identifier
numbers, but it _is_ late.

Multiple ND has
> its problems and is non-trivial to implement.

Don't know about other kernel designs, but in bsd based ones like
IRIX, `non-trivial' is an understatement :-)  I know, I already
looked into it.

> the API is broken (and easily fixed).  

I agree absolutely with the second sentance.  As an implementor, I
don't like site-local at all because it causes a multitude of problems
and I have yet to hear a convincing argument as to their merit; but
this list has already been down that path ad-nauseum and I don't want
to start this thread again; the decision has been so I apologise
for touching on the subject again :-)

> I'll point out that site-local

Agreed, as per above.

Cheers,
Sam.

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Sam Manthorpe, SGI.  tel: (650)933-2856 fax: (650)932-2856  [email-masked]
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From: Ignatios Souvatzis <[email-masked]>
Date: Sun, 21 Nov 1999 11:48:16 +0100

> numbers, but it _is_ late.

uhm... shouldn't you have a routing table set up to use site local addresses?

	-is

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From: Bill Sommerfeld <[email-masked]>
Date: Sun, 21 Nov 1999 09:51:47 -0500

> uhm... shouldn't you have a routing table set up to use site local addresses?

Your system may have interfaces connected to multiple sites who are
using the same site-local addresses.  that's why you need some sort of
scope id.

I'd rather jam a scope id into a "reserved" part of the address than
have to effectively expand addresses to 20 bytes.. (but i'd also
rather just kill site-local addresses..)

					 - Bill

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From: Jim Bound <[email-masked]>
Date: Sun, 21 Nov 1999 14:50:55 -0500

brian,

Not liking sitelocal addresses has nothing to do with the API.  The API
is just a symptom of the core problem.

And those standards are not full standards and not even draft standards
so they can be changed.  And right now if I saw a last call for the
addressing stuff to draft standard I would object.  So I am glad this
discussion got started because until about 2 weeks ago I would have
supported the specs but because folks want to make this really
integrated and force it down we need to get it right or get rid of it.
So its a good thing we are having this discussion.

And I resent you denigrating the value of the API which is the most
exposed part of IPv6 to many users.  Of course if you have not shipped
IPv6 you could not really understand this practically, but only
theoretically.  And if one is not working on a production stack in
engineering then I can realise that the API would have less weight to
such a viewpoint than mine.

/jim

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From: [email-masked] (Sam Manthorpe)
Date: Sun, 21 Nov 1999 14:52:29 -0800 (PST)

> uhm... shouldn't you have a routing table set up to use site local addresses?

Sorry, I mean <link-local-addr> not <site-local-addr>.  The point was
that you can solve the link-local address ambiguity using simultaneous
ND on each interface.