Hi Bill, On 2012-03-07 01:08, Bill Fenner wrote: > On Mon, Mar 5, 2012 at 7:15 PM, Brian E Carpenter > <[email protected]> wrote: >> Carsten, >> >> On 2012-03-06 12:22, Carsten Bormann wrote: >>> On Mar 6, 2012, at 00:00, Brian E Carpenter wrote: >>> >>>> No, I think it's exactly *not* confused on this point. There's >>>> a distinction between the idealised URI and the produced URI; >>>> in the produced URI, "%25" stands for "%" in the idealised URI. >>> Ah, so the ABNF is wrong >> I don't believe so. The ABNF does not describe the produced (encoded) >> URI. I have read sections 2.2 and 2.4 of RFC 3986 several times >> before asserting this. Of course I could be wrong, but we are waiting >> for a review from [email protected] who will hopefully give a >> definitive answer. >> >>> and the (vague) text is meant as I read it first (it can be read in other >>> ways). >> Please indicate exactly which part of the text is ambiguous, and we'll >> change it. >> >>> Replace >>> >>> IPv6addrz = IPv6address [ "%" ZoneID ] >>> >>> by >>> >>> IPv6addrz = IPv6address [ "%25" ZoneID ] >> No. In the encoded URI that would end up as %2525. That's exactly the >> trap that RFC 3986 warns against. >> >>> >>>> We have no real choice but to use % since that was chosen years >>>> ago, and that means that the produced URI contains %25. >>> I don't know that. You could use "percent" and that would work, too. >> We could use any unreserved symbol, but that would need translation from >> the RFC 4007 format. For example we could just use Z, as in >> http://[fe80::aZen1]. >> Or we could use ~: http://[fe80::a~en1]. >> >> Would that be less confusing? > > Previous joint work between the ipv6 working group and the W3C URI > working group resulted in a decision that did not change the ABNF at > all, in 2 ways: > > 1. It used the IPvFuture extension mechanism;
Hmm. I'm not sure that was a good choice. It certainly doesn't seem natural to me. Also it seems like more work for implementors than a small extension to the existing ABNF. What's so sacred? > 2. It used a non-percent character for the separator. Yes, and I have almost convinced myself that is better. The % is certainly the worst possible choice from a clarity viewpoint. > At the time, the URI working group was very concerned about the change > in the ABNF and the use of percent where percent had not previously > been allowed. Have they changed their position here, or have they not > had a chance to comment on this change yet? It's been sent for URI review but no reply so far. > > This work was accepted as an ipv6 wg work item around IETF63 (Paris, > 2005), but the authors never pushed the document forward due to a lack > of interest in the broader community. The draft that was adopted by > the wg was > > http://tools.ietf.org/html/draft-fenner-literal-zone-01 Recently there's been definite interest in this as an operational convenience. I was pretty much unaware of the 2005 work, since that was just when I joined the IESG and life was too busy, especially during the first Paris IETF. Was there a real reason that you went for this? IPv6zone-id = 1*( unreserved / sub-delims / ":" ) We have ZoneID = 1*( unreserved / pct-encoded ) which allows anything, having noted that some operating systems use all sorts of characters in interface names. Thanks Brian -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
