Network Online Course
Lesson 2 - Communication Standards
Introduction
Synopsis
Transmitting an understandable message between two machines is complicated just because there
are so many tasks to accomplish. As well, each task can be accomplished in many ways. A
framework is required if network designers, manufacturers and programmers are to produce
products that will communicate successfully. The framework is the OSI reference model produced
by the International Standards Organization. In this chapter, you will learn why standards
are important, what the OSI model is and how information is transmitted between machines using it.
Lesson Index
A. Why standards?
B. The OSI reference model
C. Internetworking devices
Review and Final Exercise
Lesson Objectives
Upon completion of this section, students will:
- Understand the importance of communication standards and why communications would not have
advanced to their current state without them.
- Have been exposed to the seven layer OSI model of communications, particularly the goals of
the model and the functions of each of the layers.
- Appreciate the relationship of internetworking devices, such as repeaters, bridges, routers
and gateways, to the model.
Discussion
Standardization in the world of computers brings benefits to consumers and developers alike.
Microsoft’s Windows environment is the overwhelming operating system of choice for the vast
majority of desktops in the world. Because of it, users only need to learn one way of doing
things before they are productive at their office machines. Windows is a proprietary standard
because it was developed by one company, Microsoft, and remains under their control.
Communication standards, however, are generally controlled by open standards bodies, of which
the foremost is the International Standards Organization.
The ISO has produced a model of communications called the Open Systems Interconnect Reference
Model, usually just called the OSI model. Efforts to produce the model started in 1976 and it
was published in its final form in 1984. The ISO had to spearhead this work because it couldn’t
be left up to companies. First, communications is between different kinds of systems and
secondly, open systems works against companies with proprietary systems. For example, the
proprietary systems of IBM and DEC allowed them to control their customers closely.
The OSI model is the topic that students resent the most in this course, usually because they
can’t see its relevance in modern computing systems. The section on routers, bridges and
gateways is an attempt to show the model at work in one area. But be patient, the OSI model
will surface at various times in this course and in future courses as well.
Network test objectives covered in this lesson
1.6 Identify the purpose, features, and functions of the following network components –
Bridges, Routers, Gateway
2.2 Identify the seven layers of the OSI model and their functions
2.3 Identify the OSI layers at which the following network components operate – Hubs,
Switches, Bridges, Routers, Network Interface Cards, Wireless Access Point
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