Transcript Internet - Knowledge on Line

 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
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
Speed
Very
slow
Speed
Slow
Speed
High
Speed
Very
High
Speed
Type
of
Circuit
Line
9.6 kbps Ordinary
Tele line
INTERNET
BACKBONE
No of
Approx
Users
Year
Speed
12
1969
9.6 kbps
1985
56 kbps
64 kbps 64 kbps
40
digital
1.544
T1
1000
mbps
digital
45
T3
1,00,000
mbps
digital
1987 1.544 mbps
1989
45 mbps
1999
Till
date
155-1000
mbps
BASIC STRUCTURE OF INTERNET
R
R
LAN
R
R
R
R
Network
Operation
Centre
LAN
Internet
Backbone
R
R
LAN
Gateway
LAN III PC
Router
PC
Server
PC
ISP
LAN I
LAN II
PC
Stand Alone PC
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
End
User
ISP
Gateway
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://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.

 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.
UPGRADES.
FREE S/W eg FONTS,CLIP ART & GAME.
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
SubDm Domain
Group
Country
[email protected]
[email protected]
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
mil
gov
edu
E-mail Address
Web Page Address
WWW.Yahoo.com
nic
[email protected]
ap
HOST COMPUTERS ON THE
INTERNET
7000000
6000000
5000000
NUMBER
4000000
OF USERS
3000000
2000000
1000000
0
1985
1986
1987
1991
YEAR
1992
1993
1994
1999