NETWORKS
Building a computer network means opening a world of new opportunities for your business. A computer network consists of a collection of computers, printers and other equipment that is connected together so that they can communicate with each other It means flexibility, efficiency, and immediate access to information that will change the way you work, communicate and serve your customers.
What Computer Networks Do
· Share Equipment
· Share Knowledge
· Share accessibility
· Share files & applications
· Copy & send files
· Communicate with the co-workers
Types of Networks
· Networks can be designed to suit organizations of all sizes, from a single location with as few as two PCs, to the largest international corporation linking thousands of workstations
The main types are
· LAN (Intranet)
· MAN (Extranet)
· WAN (Internet)
Key Internet Features
– Geographic Distribution
The geographic distribution of the Internet continues to spread, around the world and even beyond.
– Robust Architecture
The Internet is the most robust communications network ever designed, able to adapt itself almost instantaneously to damage or outages to individual sections.
– Near Light Speed
The Internet operates at near light speed, which on a planet the size of Earth often practically amounts to near real-time.
– Universal Access
The Internet provides universal access, giving the same powerful capabilities to everyone who has access to the network no matter where they are.
–The Digital Advantage
Digital communications have the D4 advantage: "Digital data doesn't degrade".
–Freedom Of Speech
Information wants to be free, and the Internet fosters freedom of speech on a global scale.
Additional Features of Internet
· Simplicity to use
· Low relative cost
· Flexibility in communications
· Security (if it secured enough)
· Speed and availability
Services given by internet
· World Wide Web
· E-mail
· Telnet
· FTP
· News Groups
· Chatting (Voice & Video)
· Search engines
· Portals
WWW(World Wide Web)
· The World Wide Web ("WWW" or simply the "Web") is a global, read-write information space.
· It was a brainchild of Tim Berners Lee
· Berners Lee conceived it as a way of publishing many linked resources over the internet.
· Text documents, images, multimedia and many other items of information, referred to as resources
Important terms in WWW
· Web Browsers
· ----- It is a program that allows the user to easily retrieve relevant information. Egs---- MOSAIC, NETSCAPE NAVIGATOR,INTERNET EXPLORER, Mozilla FireFox
· Uniform Resource Locator(URL)
· ----- Gives the type of data available and its address identifies the site in which the data belongs. unique identifiers used to locate a particular resource (computer file, document or other resource) on the network
· Eg---- http://manju.webhop.net or www.yahoo.com
· Hypertext(Hyperlinks)
· ----- the facility which allows to navigate/connect the resources in the WEB
· The user can then follow Hyperlinks in each web page to other World Wide Web resources, whose location is embedded in the hyperlinks.
· Web pages are often arranged in collections of related material called “Websites."
· The act of following hyperlinks from one website to another is referred to as “browsing" or sometimes as "surfing" the Web.
Email
· Electronic mail (abbreviated "e-mail" or, more commonly, "email") is a store and forward method of composing, sending, storing, and receiving messages over electronic communication systems.
· This facility allows to exchange mail with millions of people all over the world at economical rates
· Electronic messages are delivered to the recipient at his/her E-mail Address
Working of Email
· Sender types the message and type the E-mail Id also of the recipient.
· Immediately after “SEND” ,the message passes to the modem and then coded analog signals are sent over the service cable .
· This msg arrives at the ISP sever & is forwarded to recipients mail box.
Advantages of E-mail
· Messages can be sent any time convenient for the sender
· most economical.
· Fast Transmission takes place instantly
· Acknowledgment is possible
· Copies can sent to multiple users
· Reduces paper work
Disadvantages of E-mail
· E-mail attachments can contain viruses
· Use of false mail-id and identification problem.
· you cannot send physical objects
· messages can only be sent to other email users
· unwanted junk email may be sent to you in large amounts! - filters can be used to eliminate this
Telnet(TELetype NETwork )
· This is another important facility available in Internet
· Telnet is a software program allows internet users to access another computer linked to the internet.
· User computer is called local computer and computers to which connection is established is called Remote computer.
· Once the connection established, the local computer can give commands to the remote computer and all commands are executed by remote computer, the results can be seen in the user computer
· The user monitor displays what is taking place on the remote computer during the communication session
File Transfer Protocol(FTP)
· Is used to transfer files between computers
· Files stored on another computer can be accessed through FTP
· To gain access to the other computers , user has to supply a login name and password
· Anonymous FTP facilities are also available
· FTP works on the client / server principle
· A client program enables the user to access information and services on the server computer
· Files that can be transferred are stored on the Server computer
· A client can access these files only through a client application program
· This program helps a client computer to locate the required files to be transferred and starts the process of transfer
News Groups
· A newsgroup is a repository usually for messages posted from many users at different locations.
· A newsgroup is an Internet-based discussion about a particular topic.
· A repository is a central place where data is stored and maintained.
· Users can post their comment regarding different topics around the world
· A newsgroup is an Internet-based discussion about a particular topic.
· These topics range from sports, cars, investing, teen problems, and some stuff you probably don't want to know about.
· Users post messages to a news server which then sends them to a bunch of other participating servers.
· Then other users can access the newsgroup and read the postings.
Different topics in News Group
· comp.*: computer-related discussions (comp.software, comp.sys.amiga)
· misc.*: Miscellaneous topics (misc.education, misc.forsale, misc.kids)
· news.*: Discussions and announcements about news (meaning Usenet, not current events) (news.groups, news.admin)
· rec.*: Recreation and entertainment (rec.music, rec.arts.movies)
· sci.*: Science related discussions (sci.psychology, sci.research)
· soc.*: Social discussions (soc.college.org, soc.culture.african)
· talk.*: Talk about various controversial topics (talk.religion, talk.politics, talk.origins)
· humanities.*: Fine arts, literature, and philosophy (humanities.classics, humanities.design.misc
Search Engines
· A search engine or search service is a document retrieval system designed to help find information stored on a computer system, such as on the World Wide Web,
· The search engine allows one to ask for content meeting specific criteria (typically those containing a given word or phrase) and retrieves a list of items that match those criteria.
· Search engines use regularly updated indexes to operate quickly and efficiently.
· Without further qualification, search engine usually refers to a Web search engine, which searches for information on the public Web
· Google search is the world's most popular search engine.
Different Search Engines
· Google Relevancy uses link popularity. Clean interface.
· HotBot Advanced search capabilities available.
· Lycos Advanced search capabilities available.
Teoma.com New search engine with a clean interface
· Excite Uses Go To .com
· Wisenut.comNew search engine owned by Look Smart
· AltaVista Large index and advanced search capabilities.
· FastSearch True to its name.
· iWon.com Search and win!
· MSN Search A search engine backed by Microsoft, powered by Inktomi, Look Smart and Direct Hit
· AOL Search Backed by AOL
Types of Search engines……
· General search engines
· People search engines
· Email-based search engines
· Answer-based search engines
· Google-based search engines
· Yahoo!-based search engines
· Windows-Live-based search engines
· Job search engines
· News search engines
· Multimedia search engines
· Medical search engines
· Local search engines
· Geographic search engines
Portal
· A web portal is a website that provide an access to other resources on the internet
· A web site is said to be portal only if it provide the following services through the site
o Search and navigation
o Email
o News
o Sports
o Weather
o Real time chat
o Shopping
o Horoscope
o Message boards etc…
Types of Portals
v Horizontal portals
§ These types are general interest portals
§ Egs are Yahoo, Rediffmail, etc…….
§ They cover a wide range of interest and features.
v Vertical portals
§ These are niche portals
§ They target special audiences
§ Egs---- guru.com, ivillage.com, Boatscape, noukary.com etc.......
v Enterprise portals
§ Similar to horizontal portals, but these are offered only to corporations and similar organizations
§ Employees can visit the portals and access the news, knowledge and events.
§ Eg– IBM, Infosys, Wipro.
v Vertical industry portals (Vortals)
§ Portals which provide details of particular industry such as health care, insurance, automobiles, or food manufacturing .
§ Eg----- www.chipmaster.com is a portal covering chip making industry
§ www.ih-ra.com
Business Applications of Internet
· Benefits to computer industry
· Electronic commerce
· Access to customers
· Brand building
· HR management
· E-mail
· Dialog with customers
· Conferencing
· Entertainment Programs
