Representing the O/R Address hierarchy in the X.500 Directory Information Tree
obsoletes
- rfc-1836 — Representing the O/R Address hierarchy in the X.500 Directory Information Tree
Extracted elements (27)
ADMD is always present in the O/R Address hierarchy, including the cases of ' ' (space) and '0', because this facilitates an easy mechanical transformation between the two forms of O/R address.
Domain Defined Attributes are named by a multi-valued RDN consisting of type and value specifically so that standard attribute syntaxes can be used without defining new composite syntaxes.
mHSCountry is defined as a subclass of Country so that the same DIT entry is used for both MHS Routing and the rest of the DIT, avoiding duplication. The numeric country code is represented as an alias.
Physical Delivery (postal) addresses are not represented in this hierarchy because physical delivery is handled by the Access Unit routing mechanisms and there is no need for this representation in the DIT.
The mapping from O/R Address to Directory Name is designed so that each node is named by an attribute whose type alone can determine the reverse mapping, making the transformation mechanically reversible in both directions.
Where there are multiple domain defined attributes, the first in the sequence is the most significant, preserving the ordered semantics of X.400 DDA lists in the DIT representation.
The mapping from O/R Address to Directory Name applies only to mnemonic form, numeric form, and terminal form where country is present and X.121 addressing is used; other forms of O/R address are handled by Access Unit mechanisms.
When an X.121 address is used for fax transmission, it may only be used relative to the PRMD or ADMD, in line with current X.400 standards. This means organizational or departmental fax gateway services cannot be addressed using this form.
Where both Printable String and T.61 forms are present in an O/R Address being looked up, either may be used to construct the distinguished name; both will be represented in the DIT.
A Domain Defined Attribute generates a multi-valued RDN consisting of the mHSDomainDefinedAttributeType and mHSDomainDefinedAttributeValue attributes; aliases may not be used for domain defined attributes.
The Personal Name O/R Address component is mapped to a multi-valued RDN using the mHSPerson object class, with each component of the personal name present in the relative distinguished name.
When an O/R Address is provided but only higher components are represented in the DIT, the 'longest possible match' should be returned.
Where an O/R Address has a valid Printable String form and a T.61 form, both must be present in the DIT, with one as an alias for the other, so that direct lookup works independent of the variant used.
aDMD is an object class (subclass of top) that must contain the aDMDName attribute, a subtype of name with DirectoryString syntax up to ub-domain-name-length. It represents the Administrative Management Domain component of an O/R Address.
mHSCountry is an object class defined as a subclass of country, with an optional mHSNumericCountryName attribute (NumericString, size 1..ub-country-name-numeric-length, single value). It is the root of the O/R Address DIT hierarchy.
mHSDomainDefinedAttribute is an object class (subclass of top) that must contain both mHSDomainDefinedAttributeType and mHSDomainDefinedAttributeValue, each a single-valued subtype of name. The pair forms a multi-valued RDN so that standard attribute syntaxes can be used.
mHSOrganization is an object class (subclass of top) that must contain mHSOrganizationName, a subtype of organizationName with DirectoryString syntax up to ub-organization-name-length.
mHSOrganizationalUnit is an object class (subclass of top) that must contain mHSOrganizationalUnitName, a subtype of organizationalUnitName with DirectoryString syntax up to ub-organizational-unit-name-length. It is used for OU, OU1, OU2, OU3, and OU4 O/R Address components.
mHSPerson is an object class (subclass of top) that must contain mHSSurname and may contain mHSGivenName, mHSInitials, and mHSGenerationalQualifier. Personal name components are collectively mapped to a multi-valued RDN.
mHSTerminalID and mHSNumericUserIdentifier are object classes (subclass of top) containing mHSTerminalIDName and mHSNumericUserIdentifierName respectively, both subtypes of name. They represent terminal and numeric user identifier O/R Address components.
mHSX121 is an object class (subclass of top) that must contain mHSX121Address, a subtype of name with DirectoryString syntax up to ub-x121-address-length. It is used for X.121 form addressing, useful primarily for fax.
pRMD is an object class (subclass of top) that must contain the pRMDName attribute, a subtype of name with DirectoryString syntax up to ub-domain-name-length. It represents the Private Management Domain component.
The O/R Address hierarchy in the DIT is represented by eleven object classes ordered in Table 1: mHSCountry (mandatory), aDMD (mandatory), pRMD, mHSX121, mHSNumericUserIdentifier, mHSOrganization, mHSOrganizationalUnit, mHSPerson, mHSNamedObject, mHSTerminalID, and mHSDomainDefinedAttribute. A given object class defined higher in the table will always be higher in the DIT than one defined lower.
Appendix A assigns Object Identifiers under the mhs-ds arc {iso(1) org(3) dod(6) internet(1) private(4) enterprises(1) isode-consortium(453) mhs-ds(7) tree(2)}, defining oc (object class) and at (attribute type) sub-arcs with OIDs for all eleven object classes (oc-admd through oc-mhs-numeric-user-id) and all defined attributes (at-admd-name through at-mhs-generation-qualifier).
This protocol introduces no known security risks.
Table 2 defines the mapping from O/R Address components to X.500 object classes and naming attributes: C→mHSCountry (countryName or mHSNumericCountryName), A→aDMD (aDMDName), P→pRMD (pRMDName), O→mHSOrganization (mHSOrganizationName), OU→mHSOrganizationalUnit (mHSOrganizationalUnitName), PN→mHSPerson (personName), CN→mHSNamedObject (mHSCommonName), X121→mHSX121 (mHSX121Address), DDA→mHSDomainDefinedAttribute (type and value).
Table 3 defines keyword abbreviations for string DN representation of O/R Address attributes: e.g., aDMDName→ADMD, pRMDName→PRMD, mHSOrganizationName→MHS-O, mHSSurname→MHS-S, mHSInitials→MHS-I, mHSDomainDefinedAttributeType→MHS-DDA-Type. For example, 'I=S; S=Kille; OU1=CS; O=UCL, P=UK.AC; A=Gold 400; C=GB' becomes 'MHS-I=S + MHS-S=Kille, MHS-OU=CS, MHS-O=UCL, PRMD=UK.AC, ADMD=Gold 400, C=GB'.