Bit by bit - Unit 4 – THE INTERNET AND THE WWW

p. 65

What is the Internet?Navigate:

1 v.i. Travel in a ship, sail. L16. b Walk steadily; keep on one's course. US slang. c (Be competent to) sail a ship. L19. 2 v.t. Sail on or across (the sea, a river, etc.). b v.t. & i. transf. Make or find one's way across (an area of ground); colloq. steer (oneself, a course, etc.) through a crowd etc. c v.t. Travel, fly through, (the air). 3 a v.t. Sail, direct, manage, (a ship). L17. b v.t. Fly, manage, direct, (an aircraft, balloon, etc.). Now spec. plot and supervise the course of (an aircraft or spacecraft). c v.i. Plot and supervise the course of a motor vehicle. M20. 4 v.i. Of a ship: sail, ply.

Excerpted from Oxford Talking Dictionary. Copyright ® 1998 The Learning Company, Inc. All Rights Reserved.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

Surf:surf /sf/ n. 1 The swell of the sea which breaks upon a shore, esp. a shallow shore; an instance of this. 2 The mass or line of foam produced by this.

1 v.i. Form surf. rare. 2 v.i. Ride on the crest of a wave towards the shore by standing on a surfboard. 3 v.t. a Ride (a boat) on the surf. b Surf at (a specified place). c transf. Ride illicitly on the roof or outside of (a train). slang.

Excerpted from Oxford Talking Dictionary. Copyright ® 1998 The Learning Company, Inc. All

Rights Reserved.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

An official definition (Bit by Bit, p.65):

“The Federal Networking Council (FNC), agrees that the following language reflects our definition of the term ‘Internet’. ‘Internet’ refers to the global information system that

(i) is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons;

(ii) Is able to support communications using the Transmission Control Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP/compatible protocols;

(iii) Provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.”

In a few words: The Internet is a world-wide group of connected networks to allow publicaccess to information and services.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

What is a Protocol?

1) Protocols are the rules of communication.

2) A protocol is a method by which two computers agree to communicate. As human beings, we use language as a protocol.

3) A protocol is a standard format (created by international networking authorities) for sending and receiving information, error checking and data compression. There are lots of different types of protocols such as FTP, TFTP, BOOTP, SNMP, SMTP and MIME to name a few. The majority of protocols are implemented within the TCP/IP protocol suite.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

What is TCP/IP?

TCP/IP is a name given to the collection (or suite) of networking protocols that have been used to construct the global Internet.

TCP/IP protocols are not used only on the Internet. They are also widely used to build private networks, called internets (spelled with a small 'i'), that may or may not be connected to the global Internet (spelled with a capital 'I'). An internet that is used exclusively by one organization is sometimes called an intranet.

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How does the Internet work?

The Internet is basically a huge collection of computers that canall communicate with each other. Every computer that connectsto the Internet is given a special address called an IP address. When you connect to the Internet you become part of this hugeNetwork and so when, for example, you type in a web address youare in fact sending a request to other computers on the networkthat hold that site (computers that hold web sites are calledservers and your computer is called a client). Each request is like a package of information that your computerSends out and this package contains information about thewebsite you want to see and also the address of your computer.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

Computer networks transfer data from each anotherby packets of data. A packet is a unit of data.

Packet switching is the process in which packetsare sent in different routes to find their destination.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

IP:

• envelopes and addresses the data

• enables the network to read the envelope and forward the data to its destination

• defines how much data can fit in a single "envelope" (a packet)

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

TCP:

• breaks data up into packets that the network can handle efficiently

• verifies that all the packets arrive at their destination

• "reassembles" the data

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

An IP address is like a telephone number, except that it has decimal points in it e.g.

125.4.68.972.57.893.61

They have four sets of numbers separated by three decimal points. Each set of numbers has 1,2 or 3 numbers, but never more than 3.

Your ISP (Internet Service Provider) may give you a different IP address every time you use the Internet.

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

Who is in charge of IP Addresses?

There are 3 different address books (Regional Internet Registries) for different parts of the world.

www.ripe.net (Europe, the Middle East, Central Asia and African countries north of the equator)

www.arin.net (American Registry for Internet Numbers)www.apnic.net (Asia Pacific regions)

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

What is an Internet address?

As you have learned every computer in the Internet must have a unique and specific address. An Internet or IP address consists of four numbers separated by periods. Don't worry, only computers are expected to remember all these numbers without getting confused. For humans, we use the Domain Name System (DNS).

Bit by bit - Unit 4 – THE INTERNET AND THE WWW

What are domains?Like IP addresses which are numerical, the alphabetical domain names are

also separated by periods or dots. Thus, the U.S. Library of Congress will have an IP address of 140.147.248.7 and the domain name will be www.loc.gov. 

Domain names have the format: hostname.subdomain.top-level-domain.

Here are the existing top-level domains in the Internet: .com - commercial .edu - educational .net - network .org - organization .gov - government .mil - military Other countries sometimes add their codes at the end, such as .au for

Australia, .ph for Philippines, and .fr for France.