Introduction of internet & WWW

The internet is the global system of the interconnected computer that uses the internet protocol suite (TCP/IP) to link devices worldwide. it is a network of network that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. the internet carries a vast range of information resources and services, such as the interlinked hypertext document and applications of the world wide web (WWW), electronic mail, telephony, and file sharing.

Objective

In this chapter, we will discuss the basics of computer networks, local area networks (LAN), wide area networks (WAN), the internet, the concept of the internet, basics of internet architecture, services on the internet, the world wide web and websites, communication on the internet, internet services, and preparing computer for internet access, IAPs and example (broadband/dialup/WIFI), internet access techniques.

Basic computer network

The network is a technique that is used to make personal computers to multi-screen behaviors. Though the computer has a user multi-tasking operating system or network operating system (NOS).

By sharing resources and peripherals device more than one user can work on a single resource or device.

Type of networking

The network is divided on various grounds. there are mainly the following type of them: -

  • Based on transmission media: there are two types depending on the medium of data transmission – wired network and wireless network. Wired (twisted pair cable, coaxial cables, fiber–optic cables) and wireless (radio, microwave, infrared, satellite).
  • Based on network size: there are mainly three types depending on the internet site. LAN MAN and VAN.
  • Based on management method: it is also two types describing the internet management method. peer–to–peer and client/server.
  • Based on topology (connectivity): bus, star, ring, tree, and mesh.

Network media (transmission media)

This is the actual physical environment by which data travels from one computer to another and it connects network devices. the most basic hardware required for communication is the media through which data is transferred. there are several types of transmission media and the choice of the right media depends on many factors such as the cost of transmission media, the efficiency of data transmission, and transfer rate.

It can be divided into two main categories these are:

  1. wireless, cables, etc.,
  2. unguided:  wireless transmission, e.g., radio, microwave, and infrared waves

Guided media –

Twisted Pair Cables-

A twisted pair consists of a pair of insulated conductors that are twisted together. the advantages of a twisted pair cable over the two wire open lines are it provides better resistance from false noise signals. As the wires are closed to each other, both pick equal interferences caused by irrelevant signal sources and this reduces the differential signal added by the noise.

Coaxial cables-

The coaxial cable Is a round shape cable in which there is a main conductor Coaxial cable Is a round shape cable in which there is a main conductor wire called the inner conductor which is covered with thick plastic insulation of solid plastic, it foils above it and is wrapped in the mental wire the outer conductor is called and the top is the plastic pipe which protects all of these.

Coaxial cable is mostly used in cable tv, it is also used in computer networks, but is currently used very rarely in the computer network. The larger the cable diameter, the lower the transmission loss, and higher transfer speeds can be achieved. A co-axial cable can be used over a distance of about 1 km and can achieve a transfer rate of up to 100 Mbps.

Fiber-optic cables: These carry signals in the form of fluctuation light in a glass or plastic cable. An optical fiber cable consists of a glass or plastic core surrounded by a cladding of similar material.

The core transmits the light while the change in refractive index between the core and the cladding causes total internal reflection, thus minimizing the loss of light from the fiber.

Unguided media

Radio microwaves & satellite channels use an electromagnetic broadcast in open space. the advantages of these channels lie in their capabilities to cover large geographical areas. it is less expensive than the wired installation. the differentiation between radio, microwave & satellite channels lies in the frequencies & higher microwave frequencies.

Network-based on size

There are kinds of networks divided based on size a network within a building or campus is known as a local area network and the network which serves the entire globe is known as a wide area network.

The network is divided into three parts according to size...

  • LAN (local area network)
  • MAN (metropolitan area network)
  • VAN (wide area network)

Local area network (LAN)

 A local area network (Lan) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, or office building . a Lan is a network of connected devices that exists within a specific location. LANs may be found in homes, offices, educational, institutions, or other areas.

A LAN may be wired, wireless, or a combination of the two. A standard wired LAN uses ethernet to connect devices. Wireless LANs are typically created using a Wi-Fi signal. if a router supports both ethernet and Wi-Fi connections, it can be used to create a LAN with both wired and wireless devices.

Characteristics of LANS

The coverage area is generally a few kilometers.

Using different dedicated transmission mediums, you can achieve a transmission rate of 1 mb/s to 100 MB/sec or higher, with the further development of LAN technology currently being developed toward higher speed (e.g. 155mbps,655mbps, and 1000 Mbps, etc.)

And 1000mbps etc.

  • In LAN you can the multiple devices to share a transmission medium.
  • You can use the different topologies logy mainly bus and ring in Lan.
  • The communication quality is better n LAN, and the transmission error rate is low compared to wan.
  • Lan supports a variety of communications transmission mediums such as an ethernet cable (thin cable, thick cable, and twisted pair,), fiber, and wireless transmission.
  • A Lan usually has low cost, installation, expansion, and maintenance, and Lan installation is relatively simple good scalability.

Metropolitan area network (MAN)

A metropolitan area network (man) is a network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (Lan) but smaller than the area covered by a wide area network (wan).

Advantages of man

The biggest advantages are the bandwidth of the connecting links which means resources shared on the network can be accessed extremely quickly. some installations allow multiple users to share the same high-speed internet connection, thereby sharing the cost of the service and securing a better quality of service through collective bargaining and economies of scale.

Wide area network (WAN)

It is the biggest network in the world in that each computer is connected and shares or accesses data and information. this very network is used all the way nowadays e.g., in the finance sector, share market, and many more. Through a wide area network, we can access the information stored away on the web server in seconds.