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Internet - INFO1490 What is the Internet? - Network of networks & organizations - Each network co-operates with other networks to direct & pass Internet traffic - Co-operation requires agreement on procedure & standard protocols (TCP/IP)
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Internet - INFO1490 What is the Internet? - Network of networks & organizations - Each network co-operates with other networks to direct & pass Internet traffic - Co-operation requires agreement on procedure & standard protocols (TCP/IP) - Procedures & standards established through agreement on Requests for Comment (RFCs)
Internet - INFO1490 Groups Responsible for Overseeing the Internet - Internet Society – private, non-profit group, oversees IAB - Internet Engineering Task Force (IETF) – responsible for TCP/IP protocols - World Wide Web Consortium (W3C) – responsible for WWW standards - Internet Architecture Board (IAB) – handles Internet infrastructure
Internet - INFO1490 Organizations making up the Internet - Registrars – private companies overseeing Internet domain registration - Individual local networks – owned by private companies, universities, government agencies & online services - ISPs – provide Internet access to individuals & companies for a fee -Regional networks – consortiums of local networks - Backbone providers – large organizations such as NASA, NSF & private corporations
Internet - INFO1490 History – An Internet Timeline 1969 – U.S. DoD funds ARPANET 1972 - 1st E-mail program written 1974 - 1st definition of TCP protocol 1982 – TCP/IP protocol suite formally established as underlying protocols of Internet 1984 – Domain Name System (DNS) introduced 1986 – NSFNET backbone created with speed of 56 kbps
Internet - INFO1490 1990 - 1st commercial provider of dial-up access (The World) 1991 – World Wide Web developed by Tim Berners Lee @ CERN 1994 – Yahoo founded by Stanford graduate students 1995 - eBay founded (initially under name of Auctionweb) - Netscape goes public 1996 – Google is started by 2 Stanford grad students 1999 – Napster file-sharing software released 2000 – High speed Internet2 backbone deploys Ipv6 standard 2001 – Worms & viruses increase – examples – Code Red, Sircam
Internet - INFO1490 2004 – Online spending continues to grow – reaches 117 billion 2006 – Phone communication over Internet (VoIP) becomes more popular – ie. Vonage, Cable phones, Skype
Internet - INFO1490 Methods of Connecting to the Internet - Dial-up access through ISP or Online service (ie. AOL) - DSL high speed access through phone line to ISP - Cable high speed access through Cable TV provider (ie. Rogers, Shaw, Cogeco) - Wireless access through networks in businesses, airports, hotels, coffee shops - Cellular access using cell phones and PDAs - WebTV access through set-top box connected to TV - Access from PCs connected to internal networks with Internet access
Internet - INFO1490 Dial-up Access - Requires modem connecting PC to phone line - Steps for connection - modem dials number of ISP & connects to ISP's modem - modems connect using process called handshaking & agree on speed etc. - sending modem converts digital signal to analog signal (modulates) & sends to receiving modem across phone line - receiving modem demodulates analog signals into digital signal - connection now established & communication continues - Transmission speeds are usually 40 – 50 kbps
Internet - INFO1490 DSL High Speed Access - Requires a DSL modem connecting PC to phone line - Provides an always on connection to ISP - Only use a small portion of bandwidth of analog phone line - Allows analog phone transmission while transmitting data - Distance between sending & receiving DSL modems & thickness of copper wire affect transmissions - Transmission speeds can be from 2 to 8 Mbps for receipt of data & as low as 640 Kbps for transmission of data (asynchronous)
Internet - INFO1490 Cable High Speed Access - Requires a cable modem connecting PC to co-axial TV cable - Cable feed into home carries both TV & computer signals simultaneously on different channels (computer signals on 6Mhz channel) - Cable company divides towns into neighborhoods of approx. 500 homes & businesses called a node - Connection between homes & node is through co-axial cable - Nodes connected to head end cable facility via high speed fibre optic line - Head end cable facility handles 4-10 towns & is responsible for delivering TV & Internet access