RFC 1026 (rfc1026) - Page 2 of 4
Addendum to RFC 987: (Mapping between X
Alternative Format: Original Text Document
RFC 1026 September 1987 There are three places where an order must be specified: 1) On the text encoding (std-orname) of P1.ORName as used in the local-part of an RFC-822 address, the most significant component must be on the RHS. This applies only to those components which may have multiple values (Organisational Unit, and Domain Defined Attributes). Other attributes may be presented in any order. Note that in dmn-orname specified in Appendix F, this ordering is already implied by the current ordering requirements. 2) For the Organisational Units (OU) in P1.ORName, the first OU in the SEQUENCE is the most signicicant. This follows the "natural" hierarchy of the specification of P1.ORName, where the most significant components are defined first. 3) For the Domain Defined Attributes in P1.ORName, the First Domain Defined Attribute in the SEQUENCE is the most significant. Note that although the ordering defined in 2) and 3) is mandatory for this mapping, there are NO implications on ordering significance within X.400. 3. Extensions To Deal with Omitted Components Implementation of RFC-987 has proved to be a little inflexible for some naming strategies. In particular, there are some difficulties where Organisation or PRMD is omitted: The following sentence of RFC-987 should be removed: 4.2.1 (Page 27): "If one of the hierarchical components is omitted .... tuple).". The strategy proposed is to introduce the concept of explicit missing components to the symmetrical mapping described in 4.2.1. Essentially, a domain may be associated with an omitted attribute in conjuction with several present ones. When performing the algorithmic insertion of components lower in the hierarchy, the omitted value should be skipped. For example, if "GMD.DFN" is associated with "C=DE", "ADMD=DBP", "PRMD=GMD", and omitted organisation, then "ZI.GMD.DFN" is mapped with "C=DE", "ADMD=DBP", "PRMD=GMD", "OU=ZI". It should be noted that attributes may have null values, and that this is treated separately from omitted attributes (whilst it would be bad practice to treat these two cases differently, they must be allowed for in practice). Kille
