Network Working Group                                           S. Kille
Request for Comments: 1836                              ISODE Consortium
Category: Experimental                                       August 1995


            Representing the O/R Address hierarchy in the
                   X.500 Directory Information Tree

Status of this Memo

  This memo defines an Experimental Protocol for the Internet
  community.  This memo does not specify an Internet standard of any
  kind.  Discussion and suggestions for improvement are requested.
  Distribution of this memo is unlimited.

Abstract

  This document defines a representation of the O/R Address hierarchy
  in the Directory Information Tree [6, 1].  This is useful for a range
  of purposes, including:

o  Support for MHS Routing [4].

o  Support for X.400/RFC 822 address mappings [2, 5].

                Object Class               Mandatory
                ------------               ---------
                mHSCountry                 M
                aDMD                       M
                pRMD                       O
                mHSX121                    O
                mHSNumericUserIdentifier   O
                mHSOrganization            O
                mHSOrganizationalUnit      O
                mHSPerson                  O
                mHSNamedObject             O
                mHSTerminalID              O
                mHSDomainDefinedAttribute  O

        Table 1:  Order of O/R Address Directory Components

1.  The O/R Address Hierarchy

  An O/R Address hierarchy is represented in the X.500 directory by
  associating directory name components with O/R Address components.
  An example of this is given in Figure 1.  The object classes and
  attributes required to support this representation are defined in
  Figure 2.  The schema, which defines the hierarchy in which these



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  objects are represented in the directory information tree is
  specified in Table 1.  A given object class defined in the table will
  always be higher in the DIT than an object class defined lower down
  the table.  Valid combinations of O/R Address components are defined
  in X.400.

                                 /\
                                /   \
                   C=GB        /      \   Numeric-C=234
                              /         \
                             /            \
                            /               \
               +------------+<----------------+----+
               | Country    |                 |    |
               +------------+                 +----+
                    /\
                   /   \
                  /      \
                 /         \
    ADMD=" "    /            \  ADMD=Gold 400
    +-------------+         +------------+
    |   ADMD      |         |   ADMD     |
    +-------------+         +------------+
          \                     \
            \                     \
              \ PRMD=UK.AC          \ PRMD=UK.AC
                \                     \
               +----------+             +----+
               |  PRMD    |< -----------|    |
               +----------+             +----+
                    /
                   /
                O=UCL
                 /
                /
    +------------+
    | MHS-Org    |
    +------------+
         \
           \  OU=CS
             \
               \
             +-----------+
             | MHS-OU    |
             +-----------+

                   Figure 1:  Example O/R Address Tree




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IMPORTS
 ub-domain-name-length, ub-organization-name-length,
 ub-organizational-unit-name-length, ub-common-name-length,
 ub-x121-address-length, ub-domain-defined-attribute-type-length,
 ub-domain-defined-attribute-value-length, ub-terminal-id-length,
 ub-numeric-user-id-length, ub-country-name-numeric-length,
 ub-surname-length, ub-given-name-length,  ub-initials-length,
 ub-generation-qualifier-length

   FROM MTSUpperBounds {joint-iso-ccitt mhs-motis(6) mts(3)        10
       modules(0) upper-bounds(3) };

mHSCountry OBJECT-CLASS ::= {
   SUBCLASS OF {country}
   MAY CONTAIN {mHSNumericCountryName}
   ID oc-mhs-country}

mHSNumericCountryName ATTRIBUTE ::= {
   WITH SYNTAX NumericString (SIZE (1..ub-country-name-numeric-length))
   SINGLE VALUE                                                    20
   ID at-mhs-numeric-country-name}

aDMD OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {aDMDName}
   ID oc-admd}

aDMDName ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-domain-name-length}             30
   ID at-admd-name}

pRMD OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {pRMDName}
   ID oc-prmd}

pRMDName ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-domain-name-length}             40
   ID at-prmd-name}

mHSOrganization OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSOrganizationName }
   ID oc-mhs-organization}





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mHSOrganizationName ATTRIBUTE ::= {
   SUBTYPE OF organizationName
   WITH SYNTAX DirectoryString {ub-organization-name-length}       50
   ID at-mhs-organization-name}

mHSOrganizationalUnit OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSOrganizationalUnitName}
   ID oc-mhs-organizational-unit}

mHSOrganizationalUnitName ATTRIBUTE ::= {
   SUBTYPE OF organizationalUnitName                               60
   WITH SYNTAX DirectoryString {ub-organizational-unit-name-length}
   ID at-mhs-organizational-unit-name}

mHSPerson OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSSurname}
   MAY CONTAIN {mHSGivenName|
               mHSInitials|
               mHSGenerationalQualifier}
   ID oc-mhs-person}                                               70

mHSSurname ATTRIBUTE ::= {
   SUBTYPE OF surname
   WITH SYNTAX DirectoryString {ub-surname-lenght}
   ID at-mhs-surname}

mHSGivenName ATTRIBUTE ::= {
   SUBTYPE OF givenName
   WITH SYNTAX DirectoryString {ub-given-name-length}
   ID at-mhs-given-name}                                           80

mHSInitials ATTRIBUTE ::= {
   SUBTYPE OF initials
   WITH SYNTAX DirectoryString {ub-initials-length}
   ID at-mhs-initials}

mHSGenerationQualifier ATTRIBUTE ::= {
   SUBTYPE OF generationQualifier
   WITH SYNTAX DirectoryString {ub-generation-qualifier-length}
   ID at-mhs-generation-qualifier}                                 90

mHSNamedObject OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSCommonName}
   ID oc-mhs-named-object}




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mHSCommonName ATTRIBUTE ::= {
   SUBTYPE OF commonName
   WITH SYNTAX DirectoryString {ub-common-name-length}
   ID at-mhs-common-name}                                         100

mHSX121 OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSX121Address}
   ID oc-mhs-x121}

mHSX121Address ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-x121-address-length}
   ID at-x121-address}                                            110

mHSDomainDefinedAttribute OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {
       mHSDomainDefinedAttributeType|
       mHSDomainDefinedAttributeValue}
   ID oc-mhs-domain-defined-attribute}

mHSDomainDefinedAttributeType ATTRIBUTE ::= {
   SUBTYPE OF name                                                120
   WITH SYNTAX DirectoryString {ub-domain-defined-attribute-type-length}
   SINGLE VALUE
   ID at-mhs-domain-defined-attribute-type}

mHSDomainDefinedAttributeValue ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-domain-defined-attribute-value-length}
   SINGLE VALUE
   ID at-mhs-domain-defined-attribute-value}
                                                                  130
mHSTerminalID OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSTerminalIDName}
   ID oc-mhs-terminal-id}

mHSTerminalIDName ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-terminal-id-length}
   ID at-mhs-terminal-id-name}                                    140

mHSNumericUserIdentifier OBJECT-CLASS ::= {
   SUBCLASS OF {top}
   MUST CONTAIN {mHSNumericUserIdentifierName}
   ID oc-mhs-numeric-user-id}



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mHSNumericeUserIdentifierName ATTRIBUTE ::= {
   SUBTYPE OF name
   WITH SYNTAX DirectoryString {ub-numeric-user-id-length}        150
   ID at-mhs-numeric-user-id-name}

                   Figure 2:  O/R_Address Hierarchy

The hierarchy is defined so that:

1.  The representation is defined so that it is straightforward to
   make a mechanical transformation in either direction.  This
   requires that each node is named by an attribute whose type can
   determine the mapping.

2.  Where there are multiple domain defined attributes, the first in
   the sequence is the most significant.

3.  Physical Delivery (postal) addresses are not represented in this
   hierarchy.  This is primarily because physical delivery can be
   handled by the Access Unit routing mechanisms defined in [4], and
   there is no need for this representation.

4.  Terminal and network forms of address are not handled, except for
   X.121 form, which is useful for addressing faxes.

5.  MHSCountry is defined as a subclass of Country, and so the same
   entry will be used for MHS Routing as for the rest of the DIT.

6.  The numeric country code will be an alias.

7.  ADMD will always be present in the hierarchy.  This is true in the
   case of " " and of "0".  This facilitates an easy mechanical
   transformation between the two forms of address.

8.  Each node is named by the relevant part of the O/R Address.

9.  Aliases may be used in other parts of the tree, in order to
   normalise alternate values.  Where an alias is used, the value of
   the alias should be present as an alternate value in the node
   aliased to.  Aliases may not be used for domain defined
   attributes.

10. Domain Defined Attributes are named by a multi-valued RDN
   (Relative Distinguished Name), consisting of the type and value.
   This is done so that standard attribute syntaxes can be used.






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11. Where an O/R Address has a valid Printable String and T.61 form,
   both must be present, with one as an alias for the other.  This is
   so that direct lookup of the name will work, independent of the
   variant used.  When both are present in an O/R Address being
   looked up, either may be used to construct the distinguished name.

12. Personal name is handled by use of the mHSPerson object class.
   Each of the components of the personal name will be present in the
   relative distinguished name, which will usually be multi-valued.

  The relationship between X.400 O/R Addresses and the X.400 Entries
  (Attribute Type and Object Class) are given in Table 2.  Where there
  are multiple Organizational Units or Domain Defined Attributes, each
  component is mapped onto a single X.500 entry.

  Note: When an X.121 address is used for addressing fax transmission,
      this may only be done relative to the PRMD or ADMD. This is in
      line with the current X.400 standards position.  This means that
      it is not possible to use this form of addressing for an
      organisational or departmental fax gateway service.

O/R Address  Object Class               Naming Attribute
-----------  ------------               ----------------
C            mHSCountry                 countryName
                                       or
                                       mHSNumericCountryName
A            aDMD                       aDMDName
P            pRMD                       pRMDName
O            mHSOrganization            mHSOrganizationName
OU/OU1/OU2   mHSOrganizationalUnit      mHSOrganizationalUnitName
OU3/OU4
PN           mHSPerson                  personName
CN           mHSNamedObject             mHSCommonName
X121         mHSX121                    mHSX121Address
T-ID         mHSTerminalID              mHSTerminalIDName
UA-ID        mHSNumericUserIdentifier   mHSNumericUserIdentifierName
DDA          mHSDomainDefinedAttribute  mHSDomainDefinedAttributeType
                                       and
                                       mHSDomainDefinedAttributeValue


        Table 2:  O/R Address relationship to Directory Name









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2.  Notation

  O/R Addresses are written in the standard X.400 Notation.
  Distinguished Names use the string representation of distinguished
  names defined in [3].  The keywords used for the attributes defined
  in this specification are given in Table 3.

3.  Example Representation

  The O/R Address:

  I=S; S=Kille; OU1=CS; O=UCL,
  P=UK.AC; A=Gold 400; C=GB;


  would be represented in the directory as:

  MHS-I=S + MHS-S=Kille, MHS-OU=CS, MHS-O=UCL,

           Attribute                       Keyword
           ---------                       -------
           mHSNumericCountryName           MHS-Numeric-Country
           aDMDName                        ADMD
           pRMDName                        PRMD
           mHSOrganizationName             MHS-O
           mHSOrganizationalUnitName       MHS-OU
           mHSSurname                      MHS-S
           mHSGivenName                    MHS-G
           mHSInitials                     MHS-I
           mHSGenerationalQualifier        MHS-GQ
           mHSCommonName                   MHS-CN
           mHSX121Address                  MHS-X121
           mHSDomainDefinedAttributeType   MHS-DDA-Type
           mHSDomainDefinedAttributeValue  MHS-DDA-Value
           mHSTerminalIDName               MHS-T-ID
           mHSNumericeUserIdentifierName   MHS-UA-ID

             Table 3:  Keywords for String DN Representation


  PRMD=UK.AC, ADMD=Gold 400, C=GB










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4.  Mapping from O/R Address to Directory Name

  The primary application of this mapping is to take an X.400 encoded
  O/R Address and to generate an equivalent directory name.  This
  mapping is only used for selected types of O/R Address:

  o  Mnemonic form

  o  Numeric form

  o  Terminal form, where country is present and X121 addressing is
     used

  Other forms of O/R address are handled by Access Unit mechanisms.
  The O/R Address is treated as an ordered list, with the order as
  defined in Table 1.  For each O/R Address attribute, generate the
  equivalent directory naming attribute.  In most cases, the mapping is
  mechanical.  Printable String or Teletex encodings are chosen as
  appropriate.  Where both forms are present in the O/R Address, either
  form may be used to generate the distinguished name.  Both will be
  represented in the DIT. There are two special cases:

  1.  A DDA generates a multi-valued RDN

  2.  The Personal Name is mapped to a multi-valued RDN

  In many cases, an O/R Address will be provided, and only the higher
  components of the address will be represented in the DIT. In this
  case, the "longest possible match" should be returned.

5.  Mapping from Directory Name to O/R Address

  The reverse mapping is also needed in some cases.  All of the naming
  attributes are unique, so the mapping is mechanically reversible.

6.  Acknowledgements

  Acknowledgements for work on this document are given in [4].













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References

  [1] The Directory --- overview of concepts, models and services,
      1993. CCITT X.500 Series Recommendations.

  [2] Kille, S., "Mapping between X.400(1988)/ISO 10021 and RFC 822",
      RFC 1327, Department of Computer Science, University College
      London, May 1992.

  [3] Kille, S., "A String Representation of Distinguished Names",
      RFC 1779, Department of Computer Science, University College
      London, March 1995.

  [4] Kille, S., "MHS Use of the X.500 Directory to Support MHS
      Routing, RFC 1801, ISODE Consortium, June 1995.

  [5] Kille, S., "Use of the X.500 Directory to Support Mapping between
      X.400 and RFC 822 Addresses, RFC 1838, ISODE Consortium,
      August 1995.

  [6] CCITT recommendations X.400 / ISO 10021, April 1988. CCITT
      SG 5/VII / ISO/IEC JTC1, Message Handling:  System and Service
      Overview.

7.  Security Considerations

  Security issues are not discussed in this memo.

8.  Author's Address

  Steve Kille
  ISODE Consortium
  The Dome
  The Square
  Richmond
  TW9 1DT
  England

  Phone:  +44-81-332-9091
  Internet EMail:  [email protected]

  X.400:  I=S; S=Kille; O=ISODE Consortium; P=ISODE;
  A=Mailnet; C=FI;

  DN: CN=Steve Kille,
  O=ISODE Consortium, C=GB

  UFN: S. Kille, ISODE Consortium, GB



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A.  Object Identifier Assignment

  -----------------------------------------------------------------------
  mhs-ds OBJECT IDENTIFIER ::= {iso(1) org(3) dod(6) internet(1)
            private(4) enterprises(1) isode-consortium (453) mhs-ds (7)}


  tree OBJECT IDENTIFIER ::= {mhs-ds 2}

  oc OBJECT IDENTIFIER ::= {tree 1}
  at OBJECT IDENTIFIER ::= {tree 2}

  oc-admd OBJECT IDENTIFIER ::= {oc 1}                                10
  oc-mhs-country OBJECT IDENTIFIER ::= {oc 2}
  oc-mhs-domain-defined-attribute OBJECT IDENTIFIER ::= {oc 3}
  oc-mhs-named-object OBJECT IDENTIFIER ::= {oc 4}
  oc-mhs-organization OBJECT IDENTIFIER ::= {oc 5}
  oc-mhs-organizational-unit OBJECT IDENTIFIER ::= {oc 6}
  oc-mhs-person OBJECT IDENTIFIER ::= {oc 7}
  oc-mhs-x121 OBJECT IDENTIFIER ::= {oc 8}
  oc-prmd OBJECT IDENTIFIER ::= {oc 9}
  oc-mhs-terminal-id OBJECT IDENTIFIER ::= {oc 10}
  oc-mhs-numeric-user-id OBJECT IDENTIFIER ::= {oc 11}                20

  at-admd-name OBJECT IDENTIFIER ::= {at 1}
  at-mhs-common-name OBJECT IDENTIFIER ::= {at 2}
  at-mhs-domain-defined-attribute-type OBJECT IDENTIFIER ::= {at 3}
  at-mhs-domain-defined-attribute-value OBJECT IDENTIFIER ::= {at 4}
  at-mhs-numeric-country-name OBJECT IDENTIFIER ::= {at 5}
  at-mhs-organization-name OBJECT IDENTIFIER ::= {at 6}
  at-mhs-organizational-unit-name OBJECT IDENTIFIER ::= {at 7}
  at-prmd-name OBJECT IDENTIFIER ::= {at 10}
  at-x121-address OBJECT IDENTIFIER ::= {at 12}                       30
  at-mhs-terminal-id-name OBJECT IDENTIFIER ::= {at 13}
  at-mhs-numeric-user-id-name  OBJECT IDENTIFIER ::= {at 14}
  at-mhs-surname OBJECT IDENTIFIER ::= {at 15}
  at-mhs-given-name OBJECT IDENTIFIER ::= {at 16}
  at-mhs-initials OBJECT IDENTIFIER ::= {at 17}
  at-mhs-generation-qualifier OBJECT IDENTIFIER ::= {at 18}

  Figure 3:  Object Identifier Assignment










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