Presentation on theme: "Getting on the Internet"— Presentation transcript:
1 Getting on the Internet Internet Service ProvidersTransport MediaSending Information Back & Forth
2 Internet Service Providers (ISP) Internet Service Providers (ISP) provide you with a connection between your computer and the InternetISP 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
4 There are many ISP out there The top 3 ISP are*:AT&T with 12.9 subscribersComcast with 12.1 million subscribersAOL with 12.0 million subscribersSome 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 MediaTransport 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 LinesHome 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 linesCommon modem speeds 28.8 Kbps & 56 KbpsKbps = kilobytes per second
7 Telephone ModemFollow 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 EthernetFast Ethernet network speeds led to growth of local area networks (LANs)LANs transmit data at 10 megabits per second (Mbps)Ethernet speeds are increasingTwisted-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 ISDNIntegrated 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data over regular phone lines.ISDN carries both voice and data and supports real-time video conferencingISDNs are being superseded by Digital Subscriber Lines (DSL)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 linesDSL is available to over 75% of United StatesThere are two kinds of DSLSynchronous DSL (SDSL) uses same speed for all transmissionsAsynchronous 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 ModemsCable modems connect PCs to TV cables using both Ethernet and television signalsThe term broadband refers to these connections that carry multiple channels over a single cableSpeeds can vary depending on the number of simultaneous users on the cable’s network
13 SatelliteIf cable or DSL is not available, satellite Internet service is good if user has a view of the southern skyBad weather can impact speedsSatellite featuresTypical speeds are 500 Kbps downstream and 150 Kbps upstreamOnly 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 InternetTCP divides information into packetsTCP routes data to destinationsTCP re-assembles the informationTCP/IP are built in to the Windows and Macintosh operating systems