cs.5 computer communication and networking by rico yu
TRANSCRIPT
CS.5 Computer Communication and Networking
By Rico Yu
The need for networking Type of network Media of transmission in a network Other network devices The use of protocol E.g. of computer communication
CS.5 Computer Communication and Networking
The need for networking
Hardware sharing Communication Data and information sharing
Hardware sharing
Communication
Use network to communicate between users E-mail (電子郵件 )
Data and information sharing
Share data, files or programs E.g.
POS system Airline reservation system
Type of network
1. Local Area Network (LAN)a) Server based network
b) Peer-to-peer network
c) Terminal network
2. Wide Area Network (WAN)
Local Area NetworkLocal Area NetworkNNAALL NNAALL NNAALL NNAALL - Within a room, floor or building
FAST!
FAST!
Server based network
Peer-to-peer network
Terminal network
LANLANLANLAN
LANLAN
I Love U !I Love U too !
Wide Area NetworkWide Area NetworkNNAAWW NNAAWW NNAAWW NNAAWW - link small networks in different geographic area
Media of transmission in a network
1. Twisted pair cables
2. Coaxial cable
3. Optical fibres
4. Microwaves
5. Satellites
1. Twisted pair cables (UTP cables)
Cheapest transmission medium
Susceptible to local electrical noises
Usually used for short distance
connections such as telephone line
2. Coaxial cable
Fairly cheap transmission
mediumAn insulating material protect the copper wire
Used for connecting a TV
set to public antennaMore reliable as
it is better insulated
3. Optical fibres
- Light passes along the coated fine cylindrical glass tubing by reflection
• Very expensive transmission medium
• Not subject to electrical disturbance
• Suited for long distances communication in high data rate
4. Microwaves
5. Satellite transmission
Ground station receive the data and beam to the satellite by microwave
Satellite will re-transmit data to another ground station
5. Satellite transmission
Other network devices
1. Modem
2. Server
3. Workstation
4. Network card
5. Hub or switch
When two computers communicate to each other over a telephone lines, a modem is required for modulation and demodulation of signals.
1. Modem
Modulation : digital signals are converted to analogue signals
Demodulation : analogue signals are converted to digital signals.
1. Modem