WG ACTION: 2 weeks to discuss [LL55] 'Prevent' is too strong

Please post discussion of this issue to the mailing list over the 
next two weeks
ending May 18, 2004.  In order to accept this issued, we will need a strong WG
consensus given that this is very late in the process.

Please see http://www.drizzle.org/~aboba/ZEROCONF/issues.html for a list of
current issues and their status.

[LL55]

Description of Issue:		'Prevent' is too strong
Submitter Name:		Stuart Cheshire
Submitter Email Address:	[email protected]
Date first submitted:		04 May 04
Reference:
Comment Type ['t'ech|'e'dit]:	e
Prio ['S' Must|1 should|2 may]:	1
Section:			1.4
Rationale/Explanation:
Lengthy Description:

[Stuart]

>    In order to prevent use of IPv4 Link-Local addresses in off-link
>    communication, the following cautionary measures are advised:

"prevent" is a bit strong. How about:

>    In order to reduce the risk of accidental use of IPv4 Link-Local
>    addresses in off-link communication, the following cautionary
>    measures are advised:

[Erik]

We seek the unequivocal prevention of IPv4 LL addressses use off-link
not to reduction of the risk of their accidental use off-link.

[Stuart]

You seek unequivocal prevention, but the cautionary measures you advise
don't deliver that.

Therefore, stating that the advised cautionary measures "prevent use of
IPv4 Link-Local addresses in off-link communication" is demonstrably
false. They reduce the risk, but they don't prevent it. Either we need
stronger measures, or a weaker statement. Something needs to be fixed.

The IP address of my printer is 169.254.207.63.

There, I just used a Link-Local address in off-link communication.

Can you propose a software measure that would have unequivocally
prevented me from doing that?

No.

The general containment problem is known to be unsolvable.

There's no reason to have this kind of mistake in the document.

[Erik]

     The problem is the word 'prevent' for you means 'absolutely prevent'
     where others have not found this to be the case.  Merriam Webster
     a) to deprive of power or hoep of acting or succeeding
     b) to keep from happening or existing <steps to prevent war>
     c) to hold or keep back:  HINDER, STOP

    'in order to prevent... the following cautionary measures are advised'
     means 'We advise measures to avoid ...' not 'here is something you can
     do to absolutely  make it impossible for ... to ever occur.'

     I find your suggested wording unacceptable because we are not seeking
     to reduce the likelihood of off-link use.  This implies that in some
     sense off-link use is OK.

Requested Change:

In 1.4 change

>    In order to prevent use of IPv4 Link-Local addresses in off-link
>    communication, the following cautionary measures are advised:

to

>    In order to reduce the risk of accidental use of IPv4 Link-Local
>    addresses in off-link communication, the following cautionary
>    measures are advised: