What is the Internet? • A Short History • The Internet Today • How the Internet Works • Basic Internet Applications • Specialized Apps
What is the Internet? and Not On-Line Providers Dialup Access to Providers’ Computer Systems Gateways 7 Million Computers Seamlessly Integrated via 60,000 Largely Private Networks Gateways UUCP Nets, FidoNets, BitNets, X400,...
A Short History of the Internet • 1964—Paul Baran (RAND Corp.) proposes a loosely-coupled, robust network • 1969—ARPANET formed as a four-node network (UCLA, SRI, UCSB, and U of Utah-Salt Lake City) • 1974—Kahn and Cerf head TCP/IP project • 1980—CSNET added to ARPANET • 1986—NSF forms NSFNET
A Short History of the Internet • 1987—NSFNET “backbone” expands the Internet worldwide • 1989—CERN launches WWW project • 1990—ARPANET decommissioned • 1992—Internet Society formed • 1993—NCSA Mosaic GUI for WWW • 1995—NSFNET decomissioned
The Internet Today Connectivity Worldwide
The Internet Today 124 Million Internet Hosts 124 Million Internet Hosts hosts hosts NOW Historical Values Historical Values Projected Values Projected Values
How is the Internet Used? IRC DNS 1% APPLICATIONS 2% Gopher • FTP is the top application (based on packets transferred) • WWW is a close second 3% Telnet 3% Mail 1,075 Other 5% Services 29% NewsNet 9% WWW 20% FileTransfer 28%
How is the Internet Used? • information sharing • global collaboration • distance education • software distribution • scientific research • product development • public service • marketing & sales • customer support • professional development • entertainment some of it’s many uses...
How the Internet Works • Internet is a packet-switched network • DATAGRAMs are packets of data that also contain addressing information • TCP/IP are protocols (standards) for how datagrams are packaged and delivered • IP address is a number that signifies the address of an Internet host • Domain names are pseudonyms for IP addresses
How the Internet Works • Gateways and Routers transmit datagrams across the Internet • Client/Server applications add functionality to the Internet
Basic Internet Applications • ELECTRONIC MAIL (EMAIL)asynchronous communications • mail client • mail server
Basic Internet Applications • REMOTE LOGINS (TELNET)—synchronous 2-way communications • local host • remote host
Basic Internet Applications • FILE TRANSFER PROTOCOL (FTP)—exchanging data and programs between systems • anonymous ftp
Specialized Internet Apps • ARCHIE—searching anonymous ftp servers for files by name • GOPHER—organizing data and connections as hypertext • CHAT—“live” group conversations • MUDs & MOOs—group interactions in a virtual environment