technology guide 5 basics of the internet and the world wide web
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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 PointMAE – Metropolitan Area Exchange
The SONET
Hierarchy
Internet Backbone Circuit Capacity
See also the Mapnet project
Type of Circuit Data Rate
T1 1.544 Mbps
T3 44.74 Mbps
OC-1 51.84 Mbps
OC-3 155.52 Mbps
OC-12 622.08 Mbps
OC-24 1.244 Gbps
OC-48 2.488 Gbps
OC-192 9.95 Gbps
OC-768 39.81 Gbps
OC – Optical CarrierSONET– Synchronous Optical Networking
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 chunks of data
across the Internet concurrently • Based on the concept of turn taking, packets from each user are
alternated in the shared network
Packet Switching• Allows millions of users to send large and small chunks of data
across the Internet concurrently • Based on the concept of turn taking, packets from each user are
alternated in the shared network
Another Look at Packet Switching
How TCP/IP Work to Deliver Messages
Example: Delivering a message from Computer A to Computer D
(Computer A) TCP - Breaks message into data packetsIP - Adds address of destination Computer D
1 (Computer D) TCP - Checks for missing packets and reassembles message
3
(Router) Reads IP Address of packet, routes message to Network 2
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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?
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
TelephoneNetwork
TelephoneNetwork ISPISPDSL
ModemDSLModem
Copper Phone Line
Voice channelUpstream data channelDownstream 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 MbpsSource: Wikipedia