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Getting on the Internet

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Presentation on theme: "Getting on the Internet"— Presentation transcript:

1 Getting on the Internet
Internet Service Providers Transport Media Sending Information Back & Forth

2 Internet Service Providers (ISP)
Internet Service Providers (ISP) provide you with a connection between your computer and the Internet ISP provide varied Internet services (access to the WWW, , listservs, etc. Depending on the service, you are usually charged either by the month or by the hour

3 So who is your ISP?

4 There are many ISP out there
The top 3 ISP are*: AT&T with 12.9 subscribers Comcast with 12.1 million subscribers AOL with 12.0 million subscribers Some other ISPs include, NetZero, Earthlink, Juno, etc. Many colleges serve as an ISP, MCCC provides access to the WWW ( for faculty & staffat present). Let’s go to and see some of what else is available. *New York Times, May 3, 2007

5 Transport Media Transport medium is the physical connection which connects your computer to the internet. The Internet backbone consists of high speed fiber optic cables & copper transmission lines. This physical connection determines the speed and bandwidth capabilities of your Internet connection.

6 Using Telephone Lines Home connection using phone lines or is plain old telephone service (POTS) is still common. Modulators and demodulators (modems) send and receive digital information over analog phone lines Common modem speeds 28.8 Kbps & 56 Kbps Kbps = kilobytes per second

7 Telephone Modem Follow the signal to see how modems work by modulating the computer’s digital signal into an analog signal that can be transmitted over telephone lines to your ISP, where the signal is demodulated.

8 Ethernet Fast Ethernet network speeds led to growth of local area networks (LANs) LANs transmit data at 10 megabits per second (Mbps) Ethernet speeds are increasing Twisted-pair telephone lines are 10/100BaseT (100 megabits/second) Fiber optic speeds are 10 gigabits/second (10 Gbps) or 10 billion bits per second

9 ISDN Integrated Services Digital Network (ISDN) allows for digital transmission of data over regular phone lines. ISDN carries both voice and data and supports real-time video conferencing ISDNs are being superseded by Digital Subscriber Lines (DSL)

10 DSL DSL means Digital Subscriber Line There are two kinds of DSL
Broadband connection over telephone lines DSL is available to over 75% of United States There are two kinds of DSL Synchronous DSL (SDSL) uses same speed for all transmissions Asynchronous DSL (ADSL) uses a higher rate for downloads than uploads

11 ADSL Reduces the DSL cost. More common in home applications
Typical users download more than they upload (e.g. movies) ADSL can use the same line for simultaneous voice and data transmission while SDSL cannot

12 Cable Modems Cable modems connect PCs to TV cables using both Ethernet and television signals The term broadband refers to these connections that carry multiple channels over a single cable Speeds can vary depending on the number of simultaneous users on the cable’s network

13 Satellite If cable or DSL is not available, satellite Internet service is good if user has a view of the southern sky Bad weather can impact speeds Satellite features Typical speeds are 500 Kbps downstream and 150 Kbps upstream Only one computer can be used per subscription: DSL vendors allow more

14 Transmission Control Protocol (TCP)
Recall that TCP governs how information gets transmitted in packets over the Internet TCP divides information into packets TCP routes data to destinations TCP re-assembles the information TCP/IP are built in to the Windows and Macintosh operating systems

15 Comparing the Ways to Connect

16 Direct Connections An Internet connection that is always on is a direct connection Dial-up modems are not direct connections Direct connections are Ethernet ISDN Cable modem DSL Satellite

17 Let’s see how fast our connection is
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