Re: Are subordinate or NSSR references mandatory?

D.W.Chadwick@iti.salford.ac.uk Fri, 10 November 1995 04:51 UTC

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From: D.W.Chadwick@iti.salford.ac.uk
Date: 9 Nov 95 18:33
To: osi-ds@cs.ucl.ac.uk
Subject: Re: Are subordinate or NSSR references mandatory?
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Date: Thu, 09 Nov 95 09:20:43 EST
From: Robert Adelberg <adelberr@FHU.DISA.MIL>
Message-Id: <9510098159.AA815945809@FHU.DISA.MIL>
To: dssig@nist.gov, osi-ds@cs.ucl.ac.uk
Subject: Are subordinate or NSSR references mandatory?


     Have a question regarding references.  Fred and I at the JITC are
     preparing to revise the X.500 PICS (hopefully) for the last time and
     have come across some ambiguity in the base standard.

     Long story

     It all started with the conformance requirement for minimum knowledge,
     X.519, clause 9.2.2c. "A DSA shall conform to the minimal knowledge
     requirements defined in ITU-T Rec. X.518 | ISO/IEC 9594-4;".

     BTW, Minimum knowledge requirements are actually defined in X.501,
     clause 18.4 (unless there is a difference between minimal knowledge
     and minimum knowledge.)

     The question is our interpretation of the minimum knowledge specified
     in 18.4.1 - 18.4.4.

     18.4.1 Superior Knowledge - If the DSA is not a first-level DSA,
     superior references are mandatory.

     18.4.3 Supplier Knowledge - If the DSA consumes, supplier references
     are mandatory.

     18.4.4 Consumer Knowledge - If the DSA supplies, consumer references
     are mandatory.

     Finally,
     18.4.2 Subordinate knowledge - "A DSA that is the master DSA of a
     naming context shall maintain subordinate or non-specific subordinate
     references of category master knowledge to each master DSA holding (as
     master) an immediately subordinate naming context."

     Are we to assume that this translates into: If the DSA is not a
     centralized (solitary) DSA the subordinate OR non-specific subordinate
     reference are mandatory?
-----------------
YES. A centralised DSA does not have any immediately subordinate naming
contexts and therefore does not need to hold any subordinate references

     Centralized DSA is define in the PICS to be: a DSA that is not capable
     of holding knowledge information about other DSAs.
----------------
Wrong definition in my opinion. A centralised DSA is a DSA that holds the
entire DIT (from its perspective) i.e. no other DSAs exist (from its
perspective).

     And another thing, there is no ASN.1 definition for subordinate
     knowledge as we assume it is some conglomeration of specific and
     non-specific knowledge.
-------------
The definitions of knowledge references are in Part 2, clause 20.2.1.n (3 and 4
for subr and NSSR)

David Chadwick
Editor Part 4
     That is our interpretation, any comments on this would be appreciated.



     Rob Adelberg
     OSE Lab, JITC
     Ft. Huachuca, AZ USA