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Instructor
Note |
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The
purpose of this target indicator is for the student to
understand the importance of standards (as rules to enable
many different computers to communicate) and that
standards are institutions and processes involving people
negotiating and reaching consensus on what the rules will
be. The decision to have seven layers was made, in part,
for compatibility with IBM technology, but it also has
certain very useful layer distinctions which help in the
teaching, learning, and design of networks. |
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The early development of LANs, MANs, and WANs was chaotic in many ways. The early
1980's
saw tremendous increases in the numbers and sizes of networks. As companies realized the
money they could save and the productivity they could gain by using networking technology,
they added networks and expanded existing networks almost as rapidly as new network
technologies and products could be introduced.
By the mid-1980's, these companies began to
experience growing pains from all the expansions they had made. It became harder for
networks that used different specifications and implementations to communicate with each
other. They realized that they needed to move away from proprietary networking
systems.
Proprietary systems are privately developed, owned, and controlled. In the computer industry, proprietary is the opposite of open. Proprietary means that one or a small group of companies controls all usage of the technology.
Open means that free usage of the technology is available to the public.
To address the problem of networks being incompatible
and unable to communicate with each other, the International Organization for
Standardization (ISO) researched network schemes like DECNET,
SNA, and TCP/IP in order to find a set of rules. As a result of this research, the ISO
created a network model that would help vendors create networks that would be compatible
with, and operate with, other networks.
The
process of breaking down complex communications into smaller discrete
tasks could be compared to the process of building an automobile. When taken as a whole, the design, manufacture, and
assembly of an automobile is a highly complex process. It’s
unlikely that one single person would know how to perform all the
required tasks to build a car from scratch. This is why mechanical
engineers design the car, manufacturing engineers design the molds to
make the parts, and assembly technicians each assemble a part of the
car.
The OSI reference model
(Note: Do not confuse with ISO.), released in 1984, was the descriptive scheme they
created. It provided vendors with a set of standards that ensured greater
compatibility and interoperability between the various types of network technologies that
were produced by the many companies around the world.