RFC 1836
Representing the O/R Address hierarchy in the X.500 Directory Information Tree
Status of this Memo
Okay so this doc is RFC 1836 🎀, titled Representing the O/R Address hierarchy in the X.500 Directory Information Tree. It's from the Network Working Group, written by S. Kille of ISODE Consortium, dated August 1995, and it's filed as Experimental 🧪. The header has no Obsoletes or Updates line, so it doesn't replace or patch anything else 💅.
This memo defines an Experimental Protocol for the Internet community. It is not an Internet standard of any kind, and they're literally asking for feedback and ideas to make it better 🫶. Anyone can distribute it, no limits 🦋.
Abstract
bestie, this doc defines a representation of the O/R Address hierarchy in the Directory Information Tree [6, 1] ✨. It's super useful for a few things:
- Support for MHS Routing [4].
- Support for X.400/RFC 822 address mappings [2, 5].
Here's the lineup of the directory object classes and whether they're mandatory (M) or optional (O) 👑:
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 Components1. The O/R Address Hierarchy ✨
okay so an O/R Address hierarchy gets represented in the X.500 directory by linking directory name components to O/R Address components 💖. Figure 1 shows an example 🌸. The object classes and attributes you need for all this are defined in Figure 2, and the schema that says how these objects sit in the Directory Information Tree is in Table 1. Any object class in that table will always be higher in the DIT than any object class lower down the table 🧚. Valid combos 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 TreeNow for the ASN.1 bits, which are the real blueprint for Figure 2 🤓:
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}
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}
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}
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 HierarchyThe hierarchy is set up so that:
- The representation is defined so that it's 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.
- Where there are multiple domain defined attributes, the first in the sequence is the most significant 👑.
- 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 📮.
- Terminal and network forms of address are not handled, except for X.121 form, which is useful for addressing faxes 📠.
- MHSCountry is defined as a subclass of Country, so the same entry will be used for MHS Routing as for the rest of the DIT 💅.
- The numeric country code will be an alias 🎀.
- 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 🦋.
- Each node is named by the relevant part of the O/R Address 🌸.
- 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 🙈.
- 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 🧚.
- 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 🔍.
- 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) is 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 mHSOrganizationalUnitNameOU3/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 Name2. Notation ✨
Okay so O/R Addresses get written in the standard X.400 Notation 💅. Distinguished Names use the string representation of distinguished names from [3], so if you want the full deets, go read that one 🤓. The keywords for the attributes in this spec are listed in Table 3, which you'll see in a sec 🎀.
3. Example Representation 🦋
This example is giving everything 😭. 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,Here's the keyword table that makes it all click 💖:
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 RepresentationAnd then the rest of the string finishes off like this:
PRMD=UK.AC, ADMD=Gold 400, C=GB4. Mapping from O/R Address to Directory Name ✨
Okay, this is the main event 🔥. The whole point here is taking an X.400 encoded O/R Address and generating the matching directory name. This mapping only applies to certain types of O/R Address, namely:
- Mnemonic form
- Numeric form
- Terminal form, where country is present and X121 addressing is used
Other forms of O/R address are handled by Access Unit mechanisms, so they're not this part's problem 💅. The O/R Address gets treated as an ordered list, and that order is the one defined in Table 1. For each O/R Address attribute, you generate the equivalent directory naming attribute 🌸. Honestly, most of the time it's super mechanical. Printable String or Teletex encodings get chosen as appropriate. If both forms show up in the O/R Address, either form may be used to build the distinguished name, and both end up represented in the DIT 🦋.
There are two special cases that are extra iconic 👑:
- A DDA generates a multi-valued RDN
- The Personal Name is mapped to a multi-valued RDN
Sometimes you get an O/R Address but only the higher parts of it are represented in the DIT 🙈. In that situation, the "longest possible match" should be returned. Main character energy for the best partial match 💜.
5. Mapping from Directory Name to O/R Address 🔄
The reverse mapping is needed in some cases too 🙌. All of the naming attributes are unique, which means the mapping can be mechanically reversed. No guessing, no drama, just vibes ✨.
6. Acknowledgements 🫶
Acknowledgements for work on this document are given in [4]. Huge thank-you to everyone in there 💖.
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. So yeah, that's a whole plot point we're leaving for another day 🙈⚠️.
8. Author's Address 🎀
Steve Kille
ISODE Consortium
The Dome
The Square
Richmond
TW9 1DT
England
Phone: +44-81-332-9091
Internet EMail: S.Kille@ISODE.COM
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, GBA. 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 AssignmentThat's the whole thing, bestie 🌈💅✨
📦 where this page comes from
- ietf: rfc1836 1995-08
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms