About Internet

• The Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide.
• It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope.
• It is linked by a broad array of electronic, wireless, and optical networking technologies.

Internet Addresses:

• Because the Internet is a global network of computers each computer connected to the Internet must have a unique address.
• Internet addresses are in the form nnn.nnn.nnn.nnn where nnn must be a number from 0 – 255. This address is known as an IP address.
• The picture below illustrates two computers connected to the Internet; your computer with IP address 1.2.3.4 and another computer with IP address 5.6.7.8.

• If you connect to the Internet through an Internet Service Provider (ISP), you are usually assigned a temporary IP address for the duration of your dial-in session.
• If you connect to the Internet from a local area network (LAN) your computer might have a permanent IP address.
• In any case, if you are connected to the Internet, your computer has a unique IP address.

Internet Infrastructure:

• The Internet backbone is made up of many large networks which interconnect with each other. These large networks are known as Network Service Providers or NSPs.
• Some of the large NSPs are UUNet, CerfNet, IBM, BBN Planet, SprintNet, PSINet, as well as others. These networks peer with each other to exchange packet traffic.
• Each NSP is required to connect to three Network Access Points or NAPs.
• NSPs also interconnect at Metropolitan Area Exchanges or MAEs. MAEs serve the same purpose as the NAPs but are privately owned.
• NAPs were the original Internet interconnect points. Both NAPs and MAEs are referred to as Internet Exchange Points or IXs.
• Below is a picture showing this hierarchical infrastructure.

Internet Protocols:

• Computer protocol is a set of invisible rules that govern how an internet document gets transmitted to your screen. These programmatic rules work in the background.
• A document’s internet protocol is described by the first several letters in your browser’s address bar, ending in “://.”
• The most common protocol is http:// for a regular hypertext page, followed by https://, which governs hypertext pages that are secured against hackers.
• Examples of internet computer protocols include:
  • http: Hypertext Transfer Protocol
  • https: Hypertext Transfer Protocol Secured
  • TCP/IP: Transmission Control Protocol/Internet Protocol
  • ftp: File Transfer Protocol
  • IMAP: Internet Message Access Protocol
  • POP: Post Office Protocol
  • SMTP: Simple Mail Transfer Protocol
  • telnet: Terminal Network protocol
  • UDP: User Datagram Protocol
  • nntp: Network News Transfer Protocol
  • MAC: Media Access Control protocol
  • DNS: Domain Name System protocol
  • DHCP: Dynamic Host Configuration Protocol

Uses of Internet:

• Education and self-improvement: On-line courses and workshops have found yet another outlet.
• Electronic newspapers and magazines: This category includes late-breaking news, weather, and sports.
• Job-hunting: Classified ads are in plenty, but most are for technical positions.
• Shopping: It’s difficult to believe that this category even ranks. It appears that “cybermalls” are more for curious than serious shoppers.

• Electronic mail: Some 20 million e-mail messages cross the Internet every week.
• Research.
• Downloading files.
• Discussion groups: These include public groups, such as those on Usenet, and the private mailing lists that Listserv manages.
• Interactive games: Who hasn’t tried to hunt down at least one game?

Uses of Internet:

• All of us are familiar with the browser names like Mozilla Firefox and Internet Explorer. But the very first and popular web browser was known to be Mosaic which started its services in the year 1993 and was a major part of internet till 1997.
• There are over 1 billion internet users today which are about 20% of world’s population.
• An average surfing session lasts about only 51 minutes.
• Sweden has the greatest number of internet users across the world with about 75% of the population using it.
• The satellite-based internet availability has made it possible to access the internet all over the world.
• Asia is a continent with the largest number of internet users i.e. about 42% and about 80% of the world population still not using it.
• The first email was sent Ray Tomlinson to himself in the year 1971, he doesn’t remember the contents though.
• The fastest rate to log in to Gmail is recorded as 1.16 seconds.
• We spend more time browsing on mobile devices than on computers.
• The internet is 8352 days old.