Introduction to ICT and Programming Lecture # 3 : Internet & World Wide Web

The World of The Internet

The Internet & the World Wide Web 2.1Choosing Your Internet Access Device & Physical Connection: The Quest for Broadband 2.2Choosing Your Internet Service Provider (ISP) 2.3Sending & Receiving 2.4The World Wide Web 2.5The Online Gold Mine: More Internet Resources, Your Personal Cyberspace, E-Commerce, & the E- conomy Exploring Cyberspace

2.1Choosing Your Internet Access n This section discusses the different technologies used to connect individuals to the internet including: –1.Access device: a personal computer with a modem –2.Physical connection: a telephone line Device & Physical Connection

Physical connection n The wired or wireless means of connecting to the Internet.

Data Transmission Rates n Data is transmitted in bits per second. –bps stands for bits per second. A bit is the smallest unit of information used by computers. A computer with an older modem might have a speed of 28,800 bps per second. –Kbps stands for kilobits per second. This is the most frequently used measure. –Mbps stands for megabits per second –Gbps stands for gigabits per second

Bandwidth n - an expression of how much data can be sent through a communications channel in a given amount of time n Broadband - very high speed connection

Download & Upload n Download - to transmit data from a remote computer to a local computer n Upload - to transmit data from a local computer to a remote computer

Telephone (Dial-Up) Modem: n Modem - device that sends and receives data over telephone lines to and from computers n Most modems today have a maximum speed of 56 Kbps. Low Speed but Inexpensive & Widely Available Using a modem and phone line to establish a connection to the Internet is called making a dial-up connection.

High-Speed Phone Lines: n Integrated Services Digital network (ISDN) - hardware and software that allows voice, video, and data to be communicated over traditional copper-wire telephone lines. Speeds up to 128 kbps. n Digital Subscriber Line (DSL) - also uses regular phone lines but much faster than ISDN. Download speeds 1.5 – 8.4 Mbps n T1 - a traditional trunk line that carries 24 normal telephone circuits and has a transmission rate of 1.5 Mbps More Expensive but Available in Most Cities

High-Speed Lines n Cable : Close Competitor to DSL n Speeds up to 10 Mbps n Fiber Optics: Can support speeds up to 2 Gbps

Wireless Systems: Satellite & Other n Satellite: With a pizza-size satellite dish on your roof, you can receive data at the rate of 400 Kbps from a communications satellite, a space station that transmits radio waves called microwaves from earth-based stations. n Other wireless connections: In urban areas, some businesses are using radio waves transmitted between towers that handle cellular phone calls, which can send data at up to 155 Mbps. Through-the-Air Connections

Thank you n Thank you