Definition:A network is a way to connect computers for communication, data exchange and resourcesCommon Types of Network:LAN (Local area network )It’s a data communication system consisting of several devices such as computers and printers. in this network computers are near to each OTHER AND PHYSICALLY CONNECTED WITH CABLES WAN (Wide area network): one or more LAN’s are connected together generally across a wide a geographical area.

CHAPTER 7

NETWORKS

Hybrid Networks Between LAN and WAN structures, you will find hybrid networks such

as campus area networks (CANs) and Metropolitan area networks(MANS.

A new form of network type is emerging called home area networks(HANs)

CAMPUS AREA NETWORKS( CANs): it follows the same principle as a local area network, only on a larger and more diversified scale. Different campus , offices can be linked together.METROPOLITAN AREA NETWORKS( MANs):It’s a larger scale network that connects multiple corporate LANs together. MANs usually are not owned by single organization –their communication devices and equipment are usually maintained by group or single network provider that sells its networking services to corporate customers.

Contd… Home area networks(HANs) This network contained within a user’s home that

connects a person’s digital devices, from multiple computers and their peripheral devices e.g. Printers, telephones , VCR, DVDs.

* Peripheral devices are expensive ones such as high volume laser printers,

Intranets and extranets An intranet is the generic term for a collection

of private computer networks within an organization.

An extranet is a computer network that allows controlled access from the outside for specific business or education purposes.

Intranets and extranets are communication tools designed to enable easy information sharing within workgroups.

How Networks are structured SERVER- BASED NETWORKS Here you must know about Node. NODE is a processing location that can be a PC or some other devices such as a networked printer. Server based networks include many nodes and one or more servers which control user access to network’s resources. CLIENTS/SERVER NETWORKS Here individual computers share the processing and storage workload with a central server. This arrangement requires special software for the nodes and server.. Its can be used on LAN’s or WANs.

PEER to Peer networks In this network , all nodes on the network have equal relationships to all

others , and all have similar types of software that support the sharing of resources

What are the sophisticated tools to combat cyberslacking involving the internet?1. Web Filters: Filtering software enables companies to block employee

access to certain web sites2. Surveillance software: Software enables managers to review an

employee’s internet activities in real time e.g. uploading, downloading, chatting etc.

3. Proxy servers: This type of software can be configured to trap network traffic that is coming from or going to unauthorized source.

4. Packet Sniffers: It examine all packets being transmitted over a network. Packet sniffers are effective at detecting traffic bound for internet services e.g. FTP

Topologies Definition:Network topology is the arrangement of various elements (nodes) of a computer network.There are further topologies:1. Bus topology: this network uses one cable. All nodes and peripheral devices are

connected in a series to that cable, a special device called terminator that attach with cable’s starting and ending point, to stop network signals so they do not bounce back down the cable.

2. Star topology: All nodes are connected to a device called hub and communicate through it. Some hubs are known intelligent hubs( because they monitor traffic and help prevent collisions)

3. Ring topology: it connects the network’s nodes in a circular chain with each node connected to next. The last node connected to the first, so completing the ring

4. Mesh topology: This is the least used topology and most expensive to implement.in this a cable runs from every computer to every other computer.

Protocol:

A protocol is an agreed- upon format for transmitting data between two devices,. Some popular protocols include TCP/IP ( the internet protocol), Net-BIOS/NetBEUI

Broadband connections

DEFINITION: Broadband is used to describe any data connection that can transmit

data faster than is possible through a standard dial up connection using modem.

DSL: called digital subscriber line( DSL) is very popular especially with home users.

Cable modem connections: it enables home computer users to connect to the internet through their cable TV connection with higher speed than those offered by dial up connections

All above services are not suitable for transmitting live video and sound.as a result communications companies offer a service called ATM. This protocol designed to send voice, video and computer data over single network.