Thursday 20 November 2014

Online Communication
Online communications today is about forming connections, creating community, and organizing action in previously unimaginable ways.
Blogs, celebrity web sites and search engines are contemporaries
Video conferencing, E-mails, chat rooms etc.

Advantages 
Communication-from one place to another corner of the world
Information-any kind of news data etc
Entertainment-Movie ,songs & games download
Services- World Wide Web,Telnet ,Electronic Mail, FTP - File Transfer Protocol, Chat, Newsgroups
E-Commerce- buying and selling of products or services over electronic systems

Disadvantages
Theft of Personal information-Internet Banking
Spamming- sending unwanted e-mails in bulk
Virus threat-trojen, Melissa.A
Pornography-Portrayal of explicit content

Features Of Online Communication
·         E Mails-Electronic Mail, Unique name that consist of user name and domain name that identifies users.   E.g.- kartik_arora@gmail.com
·         Chat rooms-Typed conversation that takes place on acomputer,Yahoo messenger,Gtalk etc
·         Community websites- A virtual community is a social network of individuals who interact through specific media  
·         Facebook
·         twitter,orkut hi5
·         Blogs-Regular updated journal format to reflect interest or opinion of the author
·         Newsgroups-Online area where users discuss a particular subject
·         Websites-It is a collection of related web pages
·         E Papers-Electronic newspaper

ISP
•Short for Internet Service Provider, it refers to a company that provides Internet services, including personal and business access to the Internet. For a monthly fee, the service provider usually provides a software package, username, password and access phone number. Equipped with a modem, you can then log on to the Internet and browse the World Wide Web and USENET, and send and receive e-mail. For broadband access you typically receive the broadband modem hardware or pay a monthly fee for this equipment that is added to your ISP account billing.
•In addition to serving individuals, ISPs also serve large companies, providing a direct connection from the company's networks to the Internet. ISPs themselves are connected to one another through Network Access Points (NAPs). ISPs may also be called IAPs (Internet Access Providers).
Internet
•The term Internet has been coined from two terms, i.e., interconnection and network. A network is simply a group of computers that are connected together for sharing information and resources. Several such networks have been joined together across the world toform what is called as the Internet.
•The Internet comprises thousands of local area networks, groups of computers including government supercomputers, campus-wide information systems, local area networks and individual workstations.
•Internet Society (ISOC) defines Internet as a ‘global network of networks’ enabling computers of all kinds to directly and transparently communicate and share services throughout the world using a common communication protocol.
•There exists a set of rules which governs the the sending and receiving of data on the Internet .
•These rules are implemented in two parts in the network software and are called Transmission Control Protocol (TCP) and Internet Protocol (IP).
•These two are collectively called TCP/IP. For sending large block of text/data to another machine, TCP divides the data into little data packets. It also adds special information e.g. the packet position, error correction code etc.
•To make sure that packets at the destination can be reassembled correctly and without any damage to data. The role of IP here is to put destination addressing information on such packets
•Hypertext Transfer Protocol (HTTP)-The Hypertext Transfer Protocol (HTTP) is a set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web
•HTTP defines how browsers request web pages from servers and how servers transfer web pages to clients i.e., in essence it defines the interaction between the web client and the web server.
•HTTP request messages for the objects in the page to the server. The server receives the requests and responds with HTTP response messages that contain the objects.
•File Transfer Protocol (FTP)-FTP is a standard Internet protocol. It is the simplest way to exchange files betweencomputers on the Internet.
•FTP is commonly used to transfer web page files from their creator to the computer that acts as their server for everyone on the Internet.
•Each host computer on the Internet has its own unique address. To identify a host on the Internet, three addressing systems have been evolved: A numerical system called IP addressing, a hierarchical naming system called the Domain Name System, and an addressing system called URLs, which are used for identifying sites on the web.
•IP address: Each computer has a unique numerical address, such as 202.54.26.82
•Domain name: Each computer must have a unique name, such as www.iitd.ac.in
•Uniform Resource Locator: Address of file(s) to be accessible from a host computer

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