Re: Brian Haberman's Discuss on draft-ietf-xmpp-6122bis-23: (with DISCUSS)

Hi Brian, thanks for the review.

On 6/10/15 8:28 AM, Brian Haberman wrote:
> Brian Haberman has entered the following ballot position for
> draft-ietf-xmpp-6122bis-23: Discuss
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> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
>
> This should be a relatively straightforward DISCUSS and may not result in
> any changes to the document...
>
> I see this definition in the draft:
> domainpart   = IP-literal / IPv4address / ifqdn
>                       ;
>                       ; the "IPv4address" and "IP-literal" rules are
>                       ; defined in RFC 3986, and the first-match-wins
>                       ; (a.k.a. "greedy") algorithm described therein
>                       ; applies to the matching process
>                       ;
>                       ; note well that reuse of the IP-literal rule from
>                       ; RFC 3986 implies that IPv6 addresses are enclosed
>                       ; in square brackets (i.e., beginning with '[' and
>                       ; ending with ']')
>
> RFC 3986 was updated by RFC 6874 to allow zone identifiers in address
> literals when the address is not globally scoped.  Was this considered in
> the drafting of this update?  RFC 6874 updates the ABNF to be:
>
>        IP-literal = "[" ( IPv6address / IPv6addrz / IPvFuture  ) "]"
>        ZoneID = 1*( unreserved / pct-encoded )
>        IPv6addrz = IPv6address "%25" ZoneID
>
> I suspect you will get varying results depending on how many implementers
> follow the Updates chain of 3986.

My apologies, I forgot that RFC 6874 updated RFC 3986 in this regard. If 
we keep this text, I agree that we should point to RFC 6974.

RFC 6122 had this text:

                       ; note well that reuse of the IP-literal rule
                       ; from RFC 3986 implies that IPv6 addresses are
                       ; enclosed in square brackets (i.e., beginning
                       ; with '[' and ending with ']'), which was not
                       ; the case in RFC 3920

We could, I suppose, remove this text entirely since it was meant to 
give implementers notice about the change from RFC 3920 to RFC 6122. 
However, I think it's always good to keep implementation notes of this 
kind. So, looking at this again, I think I would change it to:

                      ; the IPv4address and IP-literal rules are
                      ; defined in RFC 3986 and RFC 6874 respectively,
                      ; and the first-match-wins (a.k.a. "greedy")
                      ; algorithm described in Appendix B of RFC 3896
                      ; applies to the matching process
                      ;
                      ; note well that reuse of the IP-literal rule from
                      ; RFC 6874 implies that IPv6 addresses are enclosed
                      ; in square brackets (i.e., beginning with '[' and
                      ; ending with ']'), which was not the case with
                      ; the definition of the XMPP address format in
                      ; RFC 3920

However, I might want to move the last paragraph to an implementation 
note (not an ABNF comment) so that we have a proper reference to RFC 6874.

Peter