OSI/MHS Configuration and Management Manual

Introduction to OSI/MHS

OSI/MHS Configuration and Management Manual—424827-003

1-28

X.400 Addressing

Addressing in an X.400 system occurs through the O/R address and route-selection

criteria. It also depends on the underlying OSI addressing, as described in Appendix D,

OSI Address Configuration in OSI/MHS.

Originator/Recipient (O/R) Address

Every OSI/MHS user has an O/R address. An O/R address is a logical address that

identifies the access point of a user to the MHS. The O/R address is unique for each

user and, therefore, distinguishes one user from another.

The O/R address identifies an MHS management domain (MD) and the user known to

that domain. Within that MHS management domain, the logical O/R address gets

mapped to a unique physical address.

The O/R address identifies the location of that user in relation to the physical and

organizational structure of the MTS. Before the MTS can transfer a message, probe,

or report, it must verify the O/R address of the user.

An O/R address is an ordered list of attributes that locate and identify a user. An

attribute has two parts:

•

Attribute type—identifies the class of information (such as personal names).

•

Attribute value—identifies a particular instance of that class (such as a particular

personal name).

An O/R address can have various forms. OSI/MHS supports the following three forms:

•

Mnemonic O/R address—identifies a user by terms that are easily recognizable.

•

Numeric O/R address—identifies a user by a number.

•

Terminal O/R address—identifies a user by a network address and includes the

type of terminal if required.

Table 1-1 shows the forms of O/R addresses and the attributes each form contains. An

uppercase letter in parentheses ( ) following an attribute name is an abbreviation

sometimes used, as in subsequent paragraphs, to designate that attribute.

Table 1-1. Forms of O/R Addresses (page 1 of 2)

O/R Address Forms

Attribute Type Mnemonic Numeric Terminal

General:

administration-domain-name (A) mandatory mandatory conditional

common-name conditional

mandatory = always present

conditional = presence or absence depends on the domain requirements