þ Network of Networks þ Nobody owns it

þ Network of Networks þ Nobody owns it þ OS - No constraint þ TCP/IP Protocol þ VPN (Virtual Private Network) þ ISP þ INTRANET

: ( ; ü ¡ Computer Telephone MODEM Account with ISP Browser Inclination

COORDINATING GROUPS OF INTERNET Internet Engineering Task Force (IETF) – Operation, Management, Evaluation & development of protocols Internet Research Task Force (IRTF) – Long term research problems and technical issues

COORDINATING GROUPS OF INTERNET Internet Architecture Board (IAB) – Overlooks the functioning of IETF & IRTF and ratifies their proposals Internet Society – Parent of IAB looks after overall promotion and usage of Internet in education, technical applications & new applications

INTERNET CONNECTIVITY DIAL-UP : For single intermittent user; uses normal telephone lines with a modem. ON DEMAND : Mid range option; Like a dedicated connection but user has to dial through a modem or ISDN (64 -128 kbps). ISDN allows both voice & data.

INTERNET CONNECTIVITY DEDICATED : For high volume use when No of users wish to simultaneously access Internet. Requires a router at the user end also. Option at different speeds are available. SATELLITE LINK RADIO LINK ISP to INTERNET – T 1 (1. 544 Mbps) or T 3 (45 Mbps) INTERNET BACKBONE – 1000 Mbps

DEDICATED CONNECTION - OPTIONS Speed Type of Circuit Line No of Approx Users INTERNET BACKBONE 9. 6 kbps Ordinary Tele line Slow Speed High Speed 64 kbps digital 1. 544 T 1 mbps digital Very High Speed 45 mbps T 3 digital 12 40 Speed 1969 9. 6 kbps 1985 Very slow Speed Year 56 kbps 1987 1. 544 mbps 1000 1989 45 mbps 1, 000 1999 Till date 155 -1000 mbps

BASIC STRUCTURE OF INTERNET R R R Network Operation Centre R R LAN ISP LAN II PC Server Router LAN III PC Building Routers Gateway PC PC Stand Alone PC LAN R ISP R Gateway Internet Backbone

TERMINOLOGY OF INTERNET BRIDGE – Connecting two NW operating with same OS ROUTER - Connecting two NW operating with different OS BROUTER – Plays both the roles of Bridge & Router ISP – Connects End-users to Internet backbone GATEWAY – A computer between ISP and Internet Router which connects the regional networks to Internet INTERNET BACKBONE – High bandwidth fiber optic line with numbers of routers End User ISP Gateway Router

DOMAIN NAME SYSTEM General Format – Host Name. Second Level Domain Name. First Level Domain Name Host Name – Service Provider Name Domain Name – Kind of Organisation Examples of Organisational & Geographic Domains gov – Government Agencies mil – Military site com – Commercial organisation net – Sites performing admin function org – Non profit organisation

INTERNET ACCOUNTS For joining Internet community registration with ISP is required. Following type of accounts are available : Dial-up Shell Account SLIP or PPP Account On Demand connection/account Leased line

TECHNOLOGY BEHIND WEB 1. URL : It is networked extension of standard file name concept. The file and its directory can exist on any computer on the network. Format of URL Protocol: //Domain. Name/Directory/Sub-dir/file http: //www. yahoo. com/abc/homepage. html 2. HTTP : Request – Response Actions of HTTP (a) Browser uses HTTP commands to commn with HTTP server through a response provided by URL. (b) A TCP/IP connection is established from client to the server. (c) Browser sends a request to server typically for a file. (d) Server sends a response message with the requested data. (e) Connection is terminated after passing the message. 3. HTML : It is based on international electronic document standard called Standard Generalised Markup Language (SGML). Common basic language of interchange for hypertext documents. Doc creation by using control codes in ASCII to designate titles, headings, graphics & hypertext links. Doc size is small.

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I Originally developed in Switzerland I Internet Navigator tool to retrieve information using links I Clients can display pages from any of ~ 5000 Web servers. I Has ability to incorporate FTP (File Transfer Protocol I Once a document is retrieved link with WWW is broken I Web page is truly MULTIMEDIA

FILE PROTOCOL TRANSFER SHAREWARE. S/W AVAILABLE ON TRIAL BASIS. FREEWARE. FREE S/W eg FONTS, CLIP ART & GAME UPGRADES. UPDATES & FIXES OF S/W. DOCUMENTS. RESEARCH PAPERS, ARTICLES etc.

IT CARRIESOUT SEARCH IN DIFFERENT WAYS AND COME OUT WITH DIFFERENT RESULTS. EACH SEARCH ENGINE HAS ITS OWN DATA BASE. IT SENDS THE ELCTRONIC CRAWLERS (CALLED SPIDERS, WORMS OR ROBOTS) THROUGH WEB LOOKING FOR PAGES TO ADD TO THEIR DATABASE OF EXISTING WEB PAGES. IT THEN ADDS THE NEW ENTRY TO THE DATABASE.

SEARCH ENGINES Site Name Alta Vista Infoseek Look Smart Lycos Yahoo Northern Light Web Crawler URL altavista. digital. com www. infoseek. com www. looksmart. com www. lycos. com www. yahoo. com www. northernlight. com www. webcrawler. com

USER AGENT IN HML TEXT AND ARE WEB PAGES. WEB BROWSERS • • INTERNET EXPLORER NETSCAPE NAVIGATOR NEOPLANET LYNX (TEXT ONLY) BROWSERS CAN READ & DISPLAY AS: • HTML FILE • EMBEDDED GRAPHIC IMAGES

User Sub. Dm Domain Group Country Cdm@ap. nic. in mohandaslv@yahoo. com

DOMAIN NAME SYSTEM Distributed Hierarchical Naming System Name is given by traversing the tree to its root At each node a name is added and period (. ) is appended Each node can have any number child nodes but only one parent node Each child node MUST have different name com in yahoo net Web Page Address WWW. Yahoo. com mil gov edu E-mail Address nic ap mohandas@ap. nic. net. in

HOST COMPUTERS ON THE INTERNET NUMBER OF USERS YEAR