InetAddressType and InetAddress in INET-ADDRESS-MIB

["Wijnen, Bert (Bert)" <bwijnen@lucent.com>]

The current I-D draft-ietf-ops-rfc2851-update-00.txt contains this TC:

   InetAddress ::= TEXTUAL-CONVENTION
       STATUS      current
       DESCRIPTION
           "Denotes a generic Internet address.

            An InetAddress value is always interpreted within the
            context of an InetAddressType value. The InetAddressType
            object which defines the context must be registered
            immediately before the object which uses the InetAddress
            textual convention. In other words, the object identifiers
            for the InetAddressType object and the InetAddress object
            MUST have the same length and the last sub-identifier of
            the InetAddressType object MUST be 1 less than the last
            sub-identifier of the InetAddress object.

            When this textual convention is used as the syntax of an
            index object, there may be issues with the limit of 128
            sub-identifiers specified in SMIv2, STD 58. In this case,
            the OBJECT-TYPE declaration MUST include a 'SIZE' clause
            to limit the number of potential instance sub-identifiers."
       SYNTAX      OCTET STRING (SIZE (0..255))

I have seen on this list (and even more in private email) discussion
on the question: Why do we need the MUST in this sentence:

                                                In other words, the object
identifiers
            for the InetAddressType object and the InetAddress object
            MUST have the same length and the last sub-identifier of
            the InetAddressType object MUST be 1 less than the last
            sub-identifier of the InetAddress object.

I think Juergen (and others) tried to explain that with this MUST rule
we can build tools/apps/code-generators that can do generic things
for such MIB objects. Fred seems to question if this indeed justifies
a MUST, because in many (most?) real applications to manipulate
a MIB, you need to know much more than the above rule, and so
you need to have humans interpret the text and mib structure
anyway (Fred I hope I am praphrasing this correctly, but I also
know you will correct me if I did not).

So the question that I want to see answered is:

- How many tools/apps/code-generators do we know about that
  indeed make use of this rule
- How does this rule help any such tools
- How important are those tools so that they justify this extra
  MUST rule?

Bert