Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

9. COMPUTER NETWORKING

 

· A Network is a way of connecting different computers to allow data and message passing, and resource sharing.

 

· Early communication techniques included telegraphs (with morris code), telephones and teletypes.

 

· Advantages

  1. - allows shared computers and peripherals
  2. - provides communication and cooperation tools for people and computers
  3. - increases reliability by having alternate computers available
  4. - decreases isolation of many computers

 

· Applications,

  1. - allows remote access to databases and libraries
  2. - electronic mail
  3. - distributed computational facilities
  4. - remote control of applications

 

· The relationship between various network types is shown below

 

· The Star Network topology uses many connections to a central server

 

· When all computers are connected to the same network cable, there are a number of structures which may be used. The bus topology below is simpler, and the tree topology is more flexible and versatile. This approach uses a single cable which is easy to add to

 

· The ring topology below shows a closed loop of cable which can be simple to implement, but limited in capabilities

 

· An enhanced ring topology is pictured below

 

· The figure below shows two ring networks, with a few possible devices hooked to them.

 

9.1 OSI NETWORK MODEL

9.2 OPEN SYSTEMS

9.3 NETWORKING HARDWARE