Chapter 6 Summary

 

Computer Network:                               

A system that connects computers and other devices (e.g. printers, smart phones) via communications media so that data can be transmitted among them.

Bandwidth:  Is for capacity and speed.

Broadband: Is multi signal capability.

 

Types of Computer Networks:

Local Area Networks (LAN):
connect two or more devices in limited region in the same building.
Every device can communicate with other  devices.
Trade-offs between:

• Speed
• Distance
• Cost

* To connect to the LAN Network/ must we have NIC Card.
* NIC Card allows the computer to connect with LAN communication.

Network Server: Control the computers in LAN communication.
* Server give us the speed.
* Server connect all the computers.


 Wide Area Networks (WAN):

• Will be in a large reign/ not limited.
• Have large capacity.
• It has a routers. ( device or modem that read the message and make a part of working).

* Example of WAN Network: Telecommunication companies and Internet.


Enterprise Networks:

Is in the organization. Example: SQU Net.
It include a complex of LAN and WAN networks.

Backbone Network: Is a speed in central network.

Networks transmit information with two types of signals:

Analog Signals: Continuous waves.                                

Have two parameters:
1- How is high
2- How is closed.

Digital Signals: Discrete pulses that are either ON or OFF , representing a series of bits (0s and 1s).

Modem:  Include moving from:

• Digital signal to analog signal (Modulator)
• Analog signal to Digital signal (Demodulator)      

 

See this video

Communication Media and Channels:

Link between two computers.

1.Wireline Media (Cable):

• Twisted-Pair Wire: Transmission will be slow and very cheap.
• Coaxial Cable: Expensive than Twisted.
• Fiber: More expensive and very fast/ use glass for wire.

2.Wireless Media (Broadcast):

• Microwave: Linking computer with country.
• Satellite: Linking computers.
• Radio: Linking computers.
• Infrared: Data can transfer from one to another/ connect to our computer and device.

Transmission Technologies:

Digital Subscriber Line (DSL):
Is a technology that provides high speed transmission of digital data . 40 Mbps.

Asynchronous Transfer Mode (ATM):

More fast than DSL, use fiber cable and it is more expensive than DSL.

Network Protocol:

Rules of network (sharing data).
Ethernet: In local network.

Transmission Control Protocol / Internet Protocol (TCP/IP): Role for using Internet.

Packet Switching: When we have a huge message we divide it into small packets.
Each packet has number to distance. Then packet get into routes.

 

Types of Network Processing:

Distributed Processing: Divide processing between two or more computers.

Client-Server Computing: Client and server sharing their work.

Peer-to-peer (P2P) processing: Each computer act both client and server.

 

The Internet and the World Wide Web:

• The Internet (“the Net”)
• Internet Service Provider (ISP)
• Addresses on the Internet
• The Internet Corporation for Assigned Names (ICANN) 
• The Web / World Wide Web / WWW/ W3
• Website
• Webpage
• Home Page
• Webmaster

Network Applications:

Discovery: To search and browse data source. Example: search engine.    



Communication:

• Electronic mail (e-mail)
• Web-based call centers 
• Electronic chat room
• Voice Communication
• Unified Communications

Collaboration: Group of people work in one site.

• Work group
• Virtual group (team)
• Virtual collaboration
• Workflow technologies
• Groupware:
• Teleconferencing
• Videoconference
• Web conferencing
•  Real-time collaboration tools.

Web services: Site that we can upload and download from it.

Telepresence Systems:

• The latest version of videoconferencing
• enable participants to seamlessly share data, voice, images, graphics, video, and animation electronically.

E-Learning:

learning supported by the Web.

Benefits:

• Students have the flexibility of learning from any place at any time at their own pace.
•  Online materials deliver high-quality, current content.
•  Training costs can be reduced.

Drawbacks:

• Instructors may need training to be able to teach electronically.
• Students must be computer literate.
• There are issues with assessing students’ work.

Telecommuting/ Teleworking:                            

Allows workers to work anytime and anyplace.
Benefits:
For employee:

• Reduced stress, improved family life
• Employment opportunities for single parents and persons with disabilities.

For Employers:

•  Increased productivity
• Ability to retain skilled employees

Drawbacks:
For employee:

• Feelings of isolation
• No workplace visibility
• Potential for slower promotions

For employers:

• Difficulties in supervising work
• Potential information security problems
• Additional training costs