OSI/MHS Configuration and Management Manual

Routing in OSI/MHS
OSI/MHS Configuration and Management Manual—424827-003
E-4
Network Types and Routing Requirements
The routing table is a finite state machine-like table containing the rules for searching
the database. The rules cover all of the following cases and vary according to which
O/R name attributes are present:
Note that any name form can result in interdomain routing. (For more information
about X.400 name forms, see X.400 Addressing on page 1-28.)
The routing algorithm is the logic that uses the routing database and routing table to
determine the route. In general, the steps taken in routing are:
1. Determine the type of O/R name in the message (X.121, numeric, or mnemonic).
2. Examine the O/R name to see which of its attributes are specified.
3. Search for a match in the routing database.
4. Queue the message for the appropriate functional unit within the MR process: the
UA access manager for message-store users, the gateway access unit for gateway
users, and the association manager for an adjacent MTA.
Network Types and Routing Requirements
Different types of network have different requirements for routing.
For example, an ADMD message switch is quite easy to configure. The only routing
objective is to define the domain to which to route the message. In this case, most
O/R name forms require that you specify only the country, the ADMD, and optionally
the PRMD. Route determination is efficient: because it typically requires only one
search of the routing database.
A configuration that includes a mixture of O/R name types, gateways, and message-
store users has additional configuration requirements. In this case, it is essential to
plan the O/R names and to define routes for all possible names. The O/R names you
associate with routes must be unique. For example, the same O/R name cannot be
assigned to a ROUTE and a DLIST, or to two APPL objects. The only exception to this
rule is that you can assign alternate routes through adjacent MTAs; in this case,
multiple routes are assigned the same O/R name, but each route is assigned a priority
so that routing requirements are unambiguous.
O/R Name Types and Routing Implications
Many types of attributes can make up a valid mnemonic O/R name. Some are
hierarchical, others are partial (for instance, omitting the organization name), and
others make use of domain-defined attributes.
•
O/R name form: X.121
•
O/R name form: numeric
•
O/R name form: mnemonic
•
Interdomain routing (to another MTA)