Industrial Communication Systems

1-1

1.1 Introduction

e ISO/OSI model was developed and standardized in the late 1970s by the International Organization

for

Standardization

as

the

standard

ISO

IS

7498.

It

supports

designers

by

easing

the

denition

of

com-

munication

protocols

in

a

way

that

they

operate

correctly

and

are

easy

to

maintain

[Hay

88].

e

name

OSI

originates

from

open

systems

interconnection.

e

model

is

not

intended

as

strict

implementation

rules,

because

a

real

system

will

always

have

to

adapt

to

requirements

of

price,

economy,

and

exibility.

Instead,

the

ISO/OSI

model

represents

an

abstract

denition

(independent

from

hardware

or

so-

ware

implementation)

consis ...