Re: [Fwd: I-D Action: draft-ietf-6man-uri-zoneid-02.txt]

Brian E Carpenter <> Mon, 16 July 2012 07:02 UTC

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Date: Mon, 16 Jul 2012 08:03:03 +0100
From: Brian E Carpenter <>
Organization: University of Auckland
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To:, Simon Perreault <>,
Subject: Re: [Fwd: I-D Action: draft-ietf-6man-uri-zoneid-02.txt]
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> The "%"
> separator is also embedded in other IETF standards-track specifications;

Can you be specific about that? The context here is very specific and
I am not aware of any other standards that are relevant to IPv6 literals.

There clearly isn't consensus in the WG on a change to the draft that can be
made before today's cutoff.

More below:

On 15/07/2012 17:49, Juergen Schoenwaelder wrote:
> On Sun, Jul 15, 2012 at 05:19:36PM +0100, Brian E Carpenter wrote:
>> ... OK, as a result of Dave's comments, we now say:
>> "  Section 11 of RFC 4007 is updated to allow "-" as well as "%" as the
>>    preceding delimiter of a ZoneID."
>> What we do *not* say is to recommend or suggest that all tools that
>> support RFC 4007 should be updated. Should we also add that?
> I believe this direction is wrong. Allowing "-" does not replace "%"
> anytime soon and hence we simply make the problem worse. 

The problem at the moment is the lack of *uniform* support for ZoneIDs
in URIs. The cause of that problem is that the delimiter chosen some years
ago is an escape charater in URIs. IMHO that was a collective error;
we would never have chosen "$" as the delimiter because everybody knows
that's an escape character in many CLIs; we just made a mistake by
overlooking that "%" is also an escape character.

The WG has already decided to fix this by adding a second delimiter "-".

> The "%"
> separator is also embedded in other IETF standards-track specifications; I
> doubt they will all be revised soon to add "-". And then there is of
> course the question what the canonical format is for comparisions etc.

Correct, we have added a reference to the IAB draft on this topic, but
comparison isn't very important for this case because the URIs concerned
have no meaning outside the originating host.

> I believe cut'n'paste from utilities to browsers and back to utilities
> is desirable (it is not just one direction). All utilities I have
> understand "%". How many years will cut'n'paste be a hassle if we
> allow both formats?

Less than infinity, which is the problem today, since most browsers simply
can't handle ZoneIDs at all.

>>From a user experience point of view, the only really sensible thing
> to do for a browser is to accept %en1 literally. And apparently, this
> can be done. 

Or not, according to which browser you consider. Remember that it was
intentionally removed from Firefox because it violates the URI standard.
And IE accepts %25en1, so we have an existing incompatibility.

> Changing all our standards to support "-" and then
> waiting years for this to be supported by all the system tools is from
> a users' perspective pretty much a disaster.

It is annoying, but seems better than having no solution at all.