What is a network?
Two or more interconnected computers.
An office network
A school network
A home network
A network is useful for communication between computers, and for sharing
resources
Communicating Sharing
Chatting Sharing a printer
Video conferencing Sharing storage
Sending e-mail Sharing Files
Playing games Internet connection
Types of networks
LANLANLocal Area Network
Local Area Network
On a small area, e.g: within one building
WANWide Area Network
How to make a network?
Networking equipment
Network Interface Card
Network Cable
Now they can communicate
But what if I have three computers?
Switch
Switch
workstation
workstation
workstation
workstation
A
B
C
D
E
Switch
back
If workstation B wants to communicate with workstation C
WAN
A WAN is made up of several connected LANsWide Area Network
It can also be a group of several WANs, or some LANs and some WANs
WAN
The Internet is the largest WAN in the world
How are LANs connectedto make a WAN ?
ROUTER
LANLAN
LAN
WAN
Router Router
WANWAN
Computers and deviceson a network
Clients & Servers• It is called a Client, because it receives services
from a Server• A Server is normally a powerful computer, that
provides services to other computers and devices on a network
Examples of serversType Service
Printer server Allows clients to print using one shared printer
Storage server Allows clients to save/store their files on a shared drive
Web server Hosts the web-pages, that are accessed by the clients
Mail server Stores clients mail accounts and inboxes. Allows clients to send email.
Storage server
Printer server
Giovanni Nick Steve
Brian James
Carola
• A firewall protects your network against unwanted access.
Firewall
• A firewall can be a hardware device and it can be software that is installed on a computer or a server.
How do you connect your network to the Internet?
1. Router 2. ISP
The Internet Service Provider, is a company, that has a very large connection to the Internet.
ISPInternet
Switch
RouterWAN
WAN
LAN
Other types of networks
LAN
Wireless Local Area Network
WLAN
Bluetooth networkPersonal Area Network PAN