Basics of Networking & Internet Services Prof. Sadique Khan

Networking  A network is a group of interconnected systems which share services and interact with each other by means of a shared communication link.  These systems can be located anywhere.

Classification of Network The most common classifications of networks are:  Local Area Networks (LAN)  Wide Area Networks (WAN)

Local Area Networks Computer network connecting Computers and other devices in a workgroup, department, building or campus.

Wide Area Networks A WAN typically consists of 2 or more LANs. The computers are farther apart and are linked by telephone lines and radio waves. The Internet is the largest Wide Area Network (WAN) in existence.

Wide Area Networks

Networking Services  Sharing of Input / Output Devices  Sharing of Software  Sharing of files residing on different computers  Communication (Electronic Mail, Chatting, broadcasting)  Electronic Trading  Sharing of Information / Exchange of data  through Web Technology over Internet

Networking Hard ware  NICs  Repeaters and Hubs  Switches  Routers

NICs Network interface cards (also called NICs, network adapters or network cards) are connectivity devices that enable a workstation, server, printer, or other node to receive and transmit data over the network media.

Repeaters and Hubs A repeater contains one input port and one output port, so it is capable only of receiving and repeating a data stream A hub is a repeater with more than one output port A hub typically contains multiple data ports into which the patch cables for network nodes are connected

Switches Switches are connectivity devices that subdivide a network into smaller logical pieces, or segments

Routers A router is a multiport connectivity device that directs data between nodes on a network Routers can integrate LANs and WANs running at different transmission speeds and using a variety of protocols

Network Example

What is Internet ?

 The Internet is “The Network of Networks”  Internet is like a phone system which connects ( almost anywhere in the world)  Exchanges information  Acts as Global link between regional networks  Allows unrestricted access Used for -Communication through , Chatting - News groups - Files transfer - Documents, data (multimedia )sharing etc

Internet: An Illustration

Model of Internet Setup Internet Media Finance Computers Real Estate Education Health Government UniversitiesBusiness Server Client

A Brief History of the Internet In the mid -1960s, mainframe computers in research organizations were stand alone devices. Computers from different manufacturers were unable to communicate with one another. The advanced research project Agency (ARPA) in the department of Defense (DoD) was interested in finding a way to connect computers.

Contd.. By 1969, ARPA was reality. Four nodes, at the University of California,University of California at santabarbara, Stanford Research Institute and University of Utah were connected via the Network.

An internet is called the internet (note the lower case letter i) is two or more networks that can communicate with each other. An internet is called the Internet (Uppercase letter I) is interconnected thousands of networks Tips

Basic Terminology used in Internet Technology  World Wide Web ( www )  Web Page  Portal  Uniform Resource Locater  Client/Server  Browser  Protocols like TCP/IP, HTTP,FTP  ISP ( Internet Service Provider )

What is the World Wide Web?

World Wide Web The World Wide Web is a repository of information linked together from points all over the world. The WWW today is a distributed client /server service, in which a client using a browser can access a service using a server.

Web Page A web Page is a single document written in HTML (Hypertext Markup Language ) that includes the text of the document, its structure, any links to other documents and graphic images and other media.

Uniform Resource Locator  Method of accessing Internet Resources  URLs are used by web browsers to connect you directly to a specific document or homepage on WWW, without having to know where that resource is physically located.

Contd.. URL defines Three Things:  Protocol  Host  Path Protocol Host name Path

Client/Server Remember, all computers on the Internet (a wide area network, or WAN) can be lumped into two groups: servers and clients, which communicate with one another. Client Server

Client  Independent computers connected to a server are called clients. Most likely, your home or office computer does not provide services to other computers. Therefore, it is a client.

Server A server is the common source that :  Provides shared services (for example, network security measures) with other machines and Manages resources (for example, one printer many people use) in a network.  The term server is often used to describe the hardware (computer), but the term also refers to the software (application) running on the computer. Many servers are dedicated, meaning they only perform specific tasks

Browser A Web Browser is special software such as Netscape, firefox or Internet Explorer. These browsers allow a user to view Web pages delivered from a client server (Web Site) situated at a particular URL on the World Wide Web.

List of Web Browser

ISP ( Internet Service Provider ) Internet Service provider is a company that offers connection to the Internet. Customer can be businesses, individuals and organization. Example:  VSNL  MTNL  Airtel

Domain Name System (DNS) This allows the IP address to be translated to words. It is much easier for us to remember a word than a series of numbers. The domain name is divided into three different section:  Generic  Country  Inverse

DNS Generic Country Inverse  Gov us 121.arpa  Com ind  Net ca  org  Info

Protocols A protocol defines what is communicated, how it is communicated and when it is communicated. Ex HTTP,IP,TCP,FTP etc.

Internet Protocol Address This number is an exclusive number all information technology devices (printers, routers, modems, et al) use which identifies and allows them the ability to communicate with each other on a computer network. Without this specific address, information cannot be received.

IP Address Example: mail.yahoo.com

How to know IP address of My Machine ?

locator.php Tracert---nslookup---ipconfig--ping

Visit the World Wide Web via the Internet Come and take your first trip into Cyber Space... It won’t be your last ! Thank You….