1. Computer Networks Part 1
LAN, WAN Adv DisAdv
Net Topology

2. Network
Collection of computers and other devices that can communicate with each other and exchange messages.
Networked computers can share:
Hardware
Software
data

3. Advantages of a network?
Reduce resource requirements
Files and files storage, printers, databases, media writers, etc.
Reduce cost
Increase efficiency and effectiveness
Improve Communication
File sharing via server
Internet, Intranet and extranet
Sharing devices such as printers saves money.
Software licences are likely to be cheaper than buying several standalone licences.
Files can easily be shared between users.
Network users can communicate by and instant messenger.
Security is good - users cannot see other users' files unlike on stand-alone machines.
Data is easy to backup as all the data is stored on the file server.

4. Network Disadvantages
Purchasing network cabling and file servers which can be expensive
Managing a large network requires a trained network manager
If the file server breaks down, the files on the file server become inaccessible
Viruses can spread to other computers throughout a computer network.
might still work if it is on a separate server. The computers can still be used but are isolated.

5. Network Terms Workstation: a computer connected to a network
Server: computer that provides services to users such as access shared files, file storage, etc.
Node: any device connected to a network

6. Types of Networks Local Area Network (LAN) Wide Area Networks (WAN)
WLAN

7. LANs: Local Area Networks
LAN covers a small area such as one site or building
LAN is often a private network that belongs to an organization or business (e.g. School or a college)
LAN uses cables or low-power radio for the connections

8. LANs: Local Area Networks

9. WANs : Wide Area Networks
WAN covers a large geographical area and large distances (states, countries, continents)
WANs are made of several LANs connected with each other
Internet is a WAN
E.g. an organization/business that has offices in different countries uses WANs to link the office LANs together

10. WANs : Wide Area Networks

11. Types of Networks
Peer-to-Peer Network
Client/Server Network

12. Peer-to-Peer Network
Allows users to access resources on other computers and share resources on their computer
All computers in Peer-to-Peer are considered equal (Same)
Each computer makes some of its resources directly available to other network computers without the need for a coordinator (server)
Advantages
Simple to setup- no technical support needed
Inexpensive
Disadvantages
Inflexible
Not secure
Limited scope (scalability

13. Peer-to-Peer Network

14. Client/Server Network
Many client computers connected to a single central server computer
A server is a host that runs server programs to share resources with clients
A client does not share any of its resources
Clients communicates with servers to request services and resources

15. Client/Server Network