Subject: Re: Summary of Issues for draft-ietf-zeroconf-ipv4-linklocal-04.txt

From: Stuart Cheshire <[email-masked]>
Date: Thu, 15 Nov 2001 14:20:02 -0800

>I'm not exactly sure what we have to compromise about?

My personal view here agrees with yours. However, the document has to 
reflect WG consensus. There can be two extremes of opinion:

A. Forget the TTL=255 test, because deployed copies of Windows since 1998 
don't work with this, and we can't break them.

B. TTL=255 is the right thing to do. Who cares about Windows?

The compromise is to say that TTL=255 is the right thing to do, but we 
also acknowledge that Windows-compatibility is of utmost importance to 
many (perhaps even the vast majority of) vendors.

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer
 * Chairman, IETF ZEROCONF
 * www.stuartcheshire.org

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From: Daniel Senie <[email-masked]>
Date: Thu, 15 Nov 2001 17:28:16 -0500

>many (perhaps even the vast majority of) vendors.

The compromise at least sets the stage for where we'd like to be going. So 
let's encourage vendors to set TTL=255, and hopefully at some point in the 
future enough will do so that the test will be usable.

Hopefully Microsoft will be willing to follow this recommendation as they 
put out new releases, and bug fixes in the future.
-----------------------------------------------------------------
Daniel Senie                                        [email-masked]
Amaranth Networks Inc.                    http://www.amaranth.com

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From: Bernard Aboba <[email-masked]>
Date: Thu, 15 Nov 2001 16:00:03 -0800 (PST)

> put out new releases, and bug fixes in the future.

New releases, perhaps. But it is unlikely that even if a fix were to be
made available, that it would be deployed to even a small fraction of the
existing installed base, many of whom are home users with little or no
understanding of networking.

Also, the fix would have to be deployed uniformly, or systems deploying
the fix would be unable to interoperate with those who don't have it. This
kind of "all or nothing" upgrade is in practice very difficult to pull
off. 

Early on, the question was asked "why do IPv4 linklocal at all?" instead
of focussing on IPv6 linklocal. The answer was backward compatibility --
systems implementing IPv6 linklocal, while interoperable with each other,
cannot communicate with existing IPv4 linklocal systems. So it was argued
that a new IPv4 linklocal specification could be backwards
compatible, thereby achieving a degree of interoperability that a
pure IPv6 linklocal approach could not. 

If we're abandoning interoperability between "new" IPv4 linklocal systems
and legacy ones, then that argument no longer holds. It would therefore
seem to make more sense to focus on implementing IPv6 linklocal in new
releases, since the interoperabilty problems won't be any worse than with
a "new" IPv4 linklocal specification.

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From: Robert Elz <[email-masked]>
Date: Fri, 16 Nov 2001 16:06:06 +0700

Date:        Thu, 15 Nov 2001 14:20:02 -0800
    From:        Stuart Cheshire <[email-masked]>
    Message-ID:  <[email-masked]>

  | My personal view here agrees with yours. However, the document has to 
  | reflect WG consensus. There can be two extremes of opinion:

I think you entirely missed the point.   I wasn't in any way suggesting
that the compromise position be altered ...

  | The compromise is to say that TTL=255 is the right thing to do, but we 
  | also acknowledge ...

that's just fine, and seems right to me.   All I want is that you not
say ...

  | that Windows-compatibility is of utmost importance to many

That is, it doesn't matter what other system is out there, or who makes
it, or what model numbers of it don't operate the way that we would prefer.

All that it is necessary to say is that there is widely deployed software (now)
that doesn't do things the way that we prefer, and that for that reason,
providing a mechanism to disable the TTL==255 test is something that 
implementors probably want to consider.

Did you actually read what I suggested replacing your suggested text with,
or did you just notice which section I was commenting on, and jump to
conclusions about what I was trying to say?

kre