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INTERNET. INTERNET. Network of Networks Nobody owns it OS - No constraint TCP/IP Protocol VPN (Virtual Private Network) ISP INTRANET. Computer Telephone MODEM Account with ISP Browser Inclination. INTERNET. COORDINATING GROUPS OF INTERNET.
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INTERNET • Network of Networks • Nobody owns it • OS - No constraint • TCP/IP Protocol • VPN (Virtual Private Network) • ISP • INTRANET
Computer • Telephone • MODEM • Account with ISP • Browser • Inclination INTERNET
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 – T1 (1.544 Mbps) or T3 (45 Mbps) INTERNET BACKBONE – 1000 Mbps
DEDICATED CONNECTION - OPTIONS INTERNET BACKBONE
BASIC STRUCTURE OF INTERNET Network Operation Centre PC PC PC PC R R R R R R R Server Router Server ISP R LAN I LAN II LAN LAN LAN Gateway Gateway Building Routers Internet Backbone LAN III ISP Stand Alone PC
End User Gate-way Gate-way End User ISP Router ISP 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
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 in – India us – USA
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://DomainName/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.
World Wide Web • WWW
WWW • Originally developed in Switzerland • Internet Navigator tool to retrieve information using links • Clients can display pages from any of ~ 5000 Web servers. • Has ability to incorporate FTP (File Transfer Protocol • Once a document is retrieved link with WWW is broken • 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.
SEARCH ENGINE ? 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 .
BROWSER • 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
. . . Internet Addressing User @ SubDm 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 gov com in mil edu net yahoo E-mail Address mohandas@ap.nic.net.in nic Web Page Address WWW.Yahoo.com ap
NUMBEROF USERS YEAR HOST COMPUTERS ON THE INTERNET