Dear all, At the IETF meeting in Minneapolis, I talked about the URI format for scoped addresses, described in http://www.ietf.org/internet-drafts/draft-fenner-literal-zone-01.txt
I had 3 questions prepared, but the time didn't really allow for asking them in a sensible way (and Dave Thaler pointed out a pre- question). So: 0. Should we solve this problem at all? The problem is of reaching [fe80::cafe:f00d] via a URI from a system attached to multiple links. (note that loopback counts as a link on some implementations.) The URI literal format (RFC 2732) didn't address this issue, so when RFC 3986 integrated this format it didn't address it either. The current proposal is to use the expansion literal format from RFC 3986, to allow a URI like http://[v6.fe80::cafe:f00d_de0]/ . If the answer is yes, then the question of a delimiter comes up. Percent, as the scoping architecture uses, is problematic because percent is such a special character in URIs. 1. Should we proceed using "_" (or some other non-percent character)? "_" fits within the current RFC 3986 grammar for the expansion of the literal format (the grammar basically reduces to the regexp \[v[0-9A-Fa-f]+\.[-0-9A-Za-z._~!$&'()*+,;=:]+\]) Note that I picked "_" after going through the ipng mailing list archives for the discussion about the scope zone format and judging that "_" had about the same amount of support as "%" in that discussion. I'm not wedded to it; if we can come to consensus on another character that is allowed by the grammar I'll be happy. If so, how should this update the scoping architecture draft? E.g., should it talk about using "_" as a seperator or just leave that to the literal URI format? 2. If not, should we proceed using "%25"? This is a percent-encoded percent, and is the only way that a percent may appear in a URI. However, even this is not allowed by the current grammar, so this would require an update to the full standard RFC 3986. 3. If not, should we proceed using "%"? A simple percent as delimiter matches with the scoping arch spec, but is even more problematic for URIs, since percents have always been so special in URIs. Even if we revised the full standard RFC 3986, it's not clear that parsers would all be properly revised (especially if the zone ID is something like "de0" - "%de0" could be a percent-encoded 0xde followed by a zero). My personal opinions are that we should proceed using "_" (or some other character), or decide that it's not important enough. It's worth solving if we can come to consensus on a lightweight solution; if we decide that we need to update RFC 3986 then I think the right path is to abandon the work. (That summarizes as "0. Yes, 1. Yes, 2. No, 3. No") Any other input? Thanks, Bill -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
