This document discusses various topics related to computer networks including transmission media, different types of network installations, types of networks like LAN, MAN, and WAN. It also covers network security tools, client-server and peer-to-peer network configurations, and common network applications like email, FTP, and the world wide web. The key purposes of networks are to enable sharing of information and hardware resources between connected systems.

1. Networking And Internet

2. Terms
• Transmission media
• Network
• Protocols

3. What Network can do?
• Exchanging Information
• Sharing hardware resources
• Preserving information
• Protecting information

4. Network Installations
• System can be installed and managed over a network in
following ways:
a) Centralized Installation
b) Distributed Installation
c) Collaborative Installation

5. Centralized Network Installation
Mainframe
100%
Computing

6. Distributed Network
Major Minor
Computing Computing

7. Collaborative network

8. Types of Network
• LAN
Links Nodes
• MAN
• WAN

9. Local Area Network

10. LAN
• Major Characteristics of LAN
•Every computer has the potential to communicate with any other
computers of the network
•High degree of interconnection between computers
•Easy physical connection of computers in a network
•Inexpensive medium of data transmission
•High data transmission rate
• Advantages
•The reliability of network is high because the failure of one computer in
the network does not effect the functioning for other computers.
•Addition of new computer to network is easy.
•High rate of data transmission is possible.
•Peripheral devices like magnetic disk and printer can be shared by other
computers.
• Disadvantages
If the communication line fails, the entire network system breaks down.

11. Metropolitan Area Networks
• The network size falls intermediate between LANs and WANs.
A MAN typically covers an area of between 5 and 50 km
diameter.
• A MAN often acts as a high speed network to allow sharing of
regional resources.

12. Wide Area Network

13. WAN
Characteristics of WAN:
1.Communication Facility
2.Remote Data Entry
3.Centralised Information

14. Network Security
• Threats to network security include:
Viruses , Trojan horse programs,
Vandals, Attacks, Data interception, Social engineering.
• Network security tools include:
Anti-virus software, Secure network infrastructure, Identity
services, Encryption, Security management

15. Network Configuration
• Client-Server based Networking
• Peer to peer networking

16. Client-Server based Networking
• Client -Server-based networking
As the name suggests server-based networking is a network
where resources, files and security are all handled by
dedicated servers. Such systems often require specialist
software such as network operating systems and hardware
such as print servers.
• Advantages
– Can easily cope with thousands of users.
– Backup, security and account control are all central.
– Software can be shared between the computers.
• Disadvantages
– If one of the servers go down all the users are affected and it may
even bring the whole network down.
– More expensive to setup and maintain.

17. Peer-to-peer networking
• Peer-to-peer networking
In peer-to-peer networking each computer has an equal status, each can use
resources such as printers and scanners from other workstations and can
communicate with the other workstations without going through a server. Peer-
to-peer networking is best used when there are only a small group of computers
which do not require regular access to the data stored on the other work stations.
• Advantages
– Easy to set up and maintain
– Inexpensive
– Will continue to operate if one of the workstations or resources malfunctions
• Disadvantages
– Because the files are stored locally on each workstation they can only be
accessed by others when that workstation is turned on.
– No central control over security or backups. Every resource and workstation
may have a different password.
– Only works well with a small number of computers

18. Network Applications
• E-mail
• Voice-mail
• FTP
• WWW
• E-commerce
• BBS User Group