RE: Where to root MIB modules

["C. M. Heard" <heard@pobox.com>]

On Mon, 5 Jan 2004, Romascanu, Dan (Dan) wrote:
> I would also suggest that the recommendation be clear when to
> pick 'mib-2' and when to pick 'transmission'. Hubmib at your
> advice rooted the Power Ethernet MIB under mib-2, and now being
> faced with questions about a new set of MIB modules for EFM,
> frankly I have no better answer then 'Mike said'.

The advice I gave for this case is based on what is written down in
the third bullet in Section 4.5 of the MIB review guidelines:

   - The value assigned to the MODULE-IDENTITY descriptor MUST be unique
     and (for IETF standards-track MIB modules) SHOULD reside under the
     mgmt subtree [RFC2578].  Most often it will be an IANA-assigned
     value directly under mib-2 [RFC2578], although for media-specific
     MIB modules that extend the IF-MIB [RFC2863] it is customary to use
     an IANA-assigned value under transmission [RFC2578].  In the past
     some IETF working groups have made their own assignments from
     subtrees delegated to them by IANA, but that practice has proven
     problematic and is NOT RECOMMENDED.

In other words, mib-2 is the default, but transmission is typically
used for MIB modules that manage specific media types.  In cases
where a MIB module is not used to manage a specific set of
transmission media then using the default (mib-2) seems to be more
appropriate.  Note that using the transmission subtree for
media-specific MIB modules is a tradition that traces back to RFC
1213, where the definition originally appeared.

//cmh