Background
Open
Systems Interconnection (OSI)
Open Systems Interconnection (OSI) is an internationally standardized
architecture that permits communications between different types
of computer systems. The elements of OSI are defined in more than
100 standards, standardized profiles and technical reports developed
by the International Organization for Standardization (ISO
),
the International Electrotechnical Commission (IEC
)
and the International Telecommunication Union (ITU
).
Fundamental to the successful operation of OSI is the ability to
identify and locate people, applications, systems, networks, and
data structures.
Names and addresses used to establish
communications must be completely unambiguous if confusion and chaos
are to be avoided. An unambiguous name is one that identifies one
and only one object within the entire open systems environment.
To ensure this unambiguity the names and addresses need to be registered.
Registration Authorities
ISO and IEC have established an international structure of registration
authorities to ensure the assignment of names and addresses that
will be unique regardless of where in the world they are used.
The Standards
Council of Canada , Canada's ISO member body, has appointed
the Government Telecommunications and Informatics Services (GTIS)
branch of Public Works and Government Services Canada (PWGSC) as
the Canadian OSI Registration Authority (COSIRA).
GTIS has also been appointed the Government
of Canada OSI Registration Authority (GORA).
The COSIRA mandate is to establish and
maintain an OSI registry of organizations and identities officially
registered in Canada. Specifically it:
- accepts and processes new applications for registration in
the OSI registry at the national level;
- ensures that all names are unique at the national level; and
- maintains and publishes the OSI registry at the national level.
The GORA mandate is to perform the same
function for Government of Canada organizations such as departments
and agencies.
Naming and Addressing
The definition of terms such as "Name"
and "Address" for OSI information objects is given in the
international standard ISO 7498-3: Information
technology -- Open Systems Interconnection -- Basic Reference
Model - Part 3: Naming and addressing. A name is a "linguistic
construct",
expressed in some language, used to identify an object.
The standards define four name spaces
for registering different types of OSI information objects:
- organization Identifiers for use in the Data Country Code (DCC)
scheme of network layer service access point (NSAP) addressing;
- object identifiers (OID) used to uniquely identify objects
such as data formats used in communications protocols and application
programs;
- "Relative Distinguished Names" (RDNs) and "Distinguished
Names"
(DNs) used in the assignment of X.500 directory names; and
- "Administrative Management Domain (ADMD)" and "Private Management
Domain (PRMD)" names used in X.400 messaging services.
Each of the name spaces forms a hierarchical
structure that is modelled as an inverted tree. ISO, IEC* and ITU
are responsible for defining the trees and registering information
objects. They have delegated responsibility for establishing and
administering registered names below the national level to their
national bodies, such as the Standards Council. The Standards Council,
in turn, has delegated functional responsibility for registration
to GTIS.
Obtaining the standards
The best source for more information on OSI is the OSI documents
themselves.
ISO and IEC standards may be obtained through IHS
Canada .
Many of ISO and IEC's OSI standards have been adopted as Canadian
standards by CSA International
. To order copies of the Canadian editions, please contact CSA.
*International Electrotechnical Commission.
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