[DNSOP] terminology: glue

[Casey Deccio <[e-mail]>]

I am still a bit uncomfortable with the -01 definition of glue,
specifically the reference to RFC 2181.  I think the reference to RFC 2181
is useful and necessary, but I hesitate to think that RFC 2181's use of
glue is a redefinition that is intended to apply outside of the RFC
itself.  That is, I believe the term was overloaded (similar to the
apparent overloading of "label" discussed in another recent dnsop thread).

Here is some proposed re-wording (modified from a previous proposal), which
both adds more context (quoted from earlier RFC 1034 text) for the use of
glue to the first paragraph and gives less weight to the RFC 2181 reference
in the second.

Glue records -- "[Records] which are not part of the
   authoritative data [for a zone], and are address resource records for
   the servers [in a subzone].  These RRs are only necessary if the name
   server's name is 'below' the cut, and are only used as part of a
   referral response."  Without glue "we could be faced with the situation
   where the NS RRs tell us that in order to learn a name server's
   address, we should contact the server using the address we wish to
   learn." (Definition from RFC 1034, section 4.2.1)

   A later definition is that glue "includes any record in a zone file
   that is not properly part of that zone, including nameserver records
   of delegated sub-zones (NS records), address records that accompany
   those NS records (A, AAAA, etc), and any other stray data that might
   appear" ([RFC2181], section 5.4.1).  Although glue is sometimes used
   today with this wider definition in mind, the context surrounding the
   RFC 2181 definition suggests it is intended to apply to the use of glue
   within document itself and not necessarily beyond.