What is Network

When connect two or more than two nodes (Device/Computer) in a system via using any physical or nonphysical medium and communicate them is called Network.

What is Internet

Internet is the world’s largest computer network, the network of networks, scattered all over the world. Its goal was to create method for widely separated computers to transfer data efficiently.

A network of networks, or “Internet”, is a group of two or more networks that are:

• Interconnected physically
• Capable of communicating and sharing data with each other
• Able to act together as a single

The internet covers the globe and includes large, international networks as well as many smaller, local-area networks (LANs). The internet offers access to data, graphics, sound, software, text, and people through a verity of services and tools for communication and data exchanges:

• Remote login (telnet)
• File transfer (ftp)
• Electronic mail (e-mail)
• News (USENET or network news)
• Hypertext (WWW)

LAN Topology

Topology is defined as the physical layout of computer, cables and other components on a network. Topology is a geometric arrangement that according connect computers in a network.

LAN Topology (Ring)

• In a ring topology all computers are connected with a cable that loops around like a circle that has no start and end, terminators are not necessary in a ring topology.
• Signals travel in one direction on a ring while they are passed from one computer to the next.
• Each device incorporates a receiver and a Transmitter.
• Each device regenerates the signal.

LAN Topology (Bus)

• All devices are connected to a common shared cable (called backbone)
• Only one computer on a bus topology can transmit a packet at a time.
• Broadcast signals in both directions on the backbone cable, enabling all devices to directly receive the signal. This means that the network is occupied until the destination computer accepts the packets.

LAN Topology (Star)

• All devices are connected to a central hub.
• Hub receives signals from other network devices and routes the signals to the proper destinations.

LAN Topology (Mesh)

• Every device is directly connected to every other device on the network.
• Data transfer can take alternative routes.

LAN Topology (Tree)

Tree can be formed in two ways:

• By connecting numbers of full network.
• By connecting numbers of star networks.

Component of LAN

Various types of component available for LAN designing:-

1. Media
   1. Physical
   2. Nonphysical
2. NOS
3. NIC
4. HUB
5. Switch
6. Router
7. Bridge
8. Gateway
9. Repeater

Component of LAN (NOS)

Various types of component available for LAN designing NOS.

An operating system that includes special functions for connecting computers and devices into a local-area network (LAN) is called Network Operating System. Some operating systems, such as UNIX and the Mac OS, have networking functions built in. The term network operating system, however, is generally reserved for software that enhances a basic ope

rating system by adding networking features. Examples of NOS are:-

1. Novell
2. Cisco
3. Microsoft Windows Server
4. Windows NT

Component of LAN (NIC)

Various types of component available for LAN designing NIC.

An expansion board you insert into a  computer so the computer can be connected to a network. Most NIC’s are designed for a particular type of network, protocol, and media, although some can serve multiple networks. NIC is also called Ethernet Card.

Component of LAN (HUB)

Various types of component available for LAN designing HUB.

A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.

Three Types of HUB

1. Passive
2. Active

Component of LAN (SWITCH)

Various types of component available for LAN designing Switch.

A network switch is a computer networking device that connects network segments or network devices. The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer 2) of the OSI model.

Component of LAN (ROUTER)

Various types of component available for LAN designing Router.

A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP’s network. Routers are located at gateways, the places where two or more networks connect.

Component of LAN (BRIDGE)

Various types of component available for LAN designing Bridge.

A device that connects two local-area networks (LANs), or two segments of the same LAN that use the same protocol, such as Ethernet or Token-Ring.

Component of LAN (GATEWAY)

Various types of component available for LAN designing Gateway.

In a communications network, a network node equipped for interfacing with another network that uses different protocols. A gateway may contain devices such as protocol translators, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide system

interoperability. It also requires the establishment of mutually acceptable administrative procedures between both networks. A protocol translation/mapping gateway interconnects networks with different network protocol technologies by performing the required protocol conversions.

Component of LAN (REPEATER)

Various types of component available for LAN designing Repeater.

A network device used to regenerate or replicate a signal. Repeaters are used in transmission systems to regenerate analog or digital signals distorted by transmission loss.

WWW & Internet

The term WWW refers to the World Wide Web or simply the Web. The World Wide Web consists of all the public Web sites connected to the Internet worldwide, including the client devices (such as computers and cell phones) that access Web content. The WWW is just one of many applications of the Internet and computer networks. The World Web is based on these technologies:

• HTML – Hypertext Markup Language
• HTTP – Hypertext Transfer Protocol
• Web servers and Web browsers

Researcher Tim Berners-Lee led the development of the original World Wide Web in the late 1980s and early 1990s. He helped build prototypes of the above Web technologies and coined the term ‘WWW’ Web sites and Web browsing exploded in.

Internet:

Internet is the world’s largest computer network, the network of networks, scattered all over the world. Its goal was to create method for widely separated computers to transfer data efficiently.

Types of Internet Connection:-

1. Dial-Up (Dial-up connection speeds range from 2400 bps to 56 Kbps)
2. ISDN / Leased Line / Broadband (ISDN speeds range from 64 Kbps to 10 Mbps)
3. Satellite (ISDN speeds range from 64 Kbps to 10 Mbps)

Dial-Up Or ISDN / Leased Line / Broadband

Satellite

Other Topic :- PC Components