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TECHNOLOGY GUIDE 5. Basics of the Internet and the World Wide Web. The Internet. Began as a government-sponsored network for research and education. Became commercialized in 1993 with the World Wide Web innovation Based on two protocols (TCP/IP) Transmission Control Protocol (TCP)
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TECHNOLOGY GUIDE 5 Basics of the Internet and the World Wide Web
The Internet • Began as a government-sponsored network for research and education • Became commercialized in 1993 with the World Wide Web innovation • Based on two protocols (TCP/IP) • Transmission Control Protocol (TCP) • Internet Protocol (IP) • Most users connect to it through an Internet Service Provider (ISP)
Architecture of the Internet NAP – Network Access Point MAE – Metropolitan Area Exchange
Internet Backbone Circuit Capacity The SONET Hierarchy OC – Optical Carrier SONET– Synchronous Optical Networking See also theMapnetproject
Identifying Computers on the Internet (Addressing) • Domain name(symbolic address) • e.g., www.csun.edu, www.yahoo.com • IP Address (numeric address) • e.g., 130.166.1.254, 130.166.105.77 • URLs (Uniform Resource Locators) – identify paths to a Web page or document • e.g., http://www.csun.edu/webmail
How the Internet Works – Packet Switching • Packet Switching • Allows millions of users to send large and small chunksof data across the Internet concurrently • Based on the concept of turn taking, packets from each user are alternated in the shared network
How TCP/IP Work to Deliver Messages Example: Delivering a message from Computer A to Computer D 2 (Router) Reads IP Address of packet, routes message to Network 2 3 1 (Computer A) TCP - Breaks message into data packets IP - Adds address of destination Computer D (Computer D) TCP - Checks for missing packets and reassembles message
Accessing the Internet (the Last Mile) • Amdahl’s Law: A network connection can be no faster than its slowest link • Speed of the Internet often limited by the local access technology (the last mile) • Broadband Internet Access (FCC): 768 kbps minimum • For HD streaming video, need at least 5 Mbps • How fast is your Internet access?
Telephone Network ISP DSL Modem Copper Phone Line Digital Subscriber Line (DSL) • Combine voice and high-speed data on a single phone line • Users do not share access lines • 1.5 – 9 Mbps downstream, 16 – 640 Kbps upstream • Distance-sensitive Voice channel Upstream data channel Downstream data channel
Cable Modem • Allocates a small portion of a cable TV system’s high bandwidth media for data transmission • 1.5 – 30 Mbps downstream, 384Kbps – 1.5 Mbps upstream
Fixed or Mobile Wireless Access • Cellular network • Internet-enabled cellular phones • User can move within cellular coverage area • Wi-Fi (WLAN) • User can move within range of a Hot Spot • Fixed wireless (WiMax) with ranges up to 50 km
Fiber to the X Service • Fiber to the Node • Fiber to the Curb • Fiber to the Building • Fiber to the Home • Sweden leads the world in FTTH • Average download speed is 86 Mbps Source: Wikipedia