Telecommunication

Telecommunication is the transmission of signs, signals, messages, words, writings, images and sounds or information of any nature by wire, radio, optical or electromagnetic systems. Telecommunication occurs when the exchange of information between communication participants includes the use of technology.

Computer Network Defined

A computer network is a set of connected computers. Computers on a network are called nodes. The connection between computers can be done via cabling, most commonly the Ethernet cable, or wirelessly through radio waves. Connected computers can share resources, like access to the Internet, printers, file servers, and others. A network is a multipurpose connection, which allows a single computer to do more.

Types of Computer Networks

LAN:  A local area network is a network that connects Local Area Network (LAN) computers and device in a limited geographical area such as a home, school computer laboratory, office building

WAN: A wide area network is a network that covers a largeWide Area Network geographical area such country or the world (WAN) WAN combines many types of media such as telephone lines, cables and radio wave. A WAN can be one large network or can consist of two or more LANs connected together The internet is the worlds largest WAN

MAN: A metropolitan area network (MAN) is a high-speed Metropolitan Area network that connects local area networks in a Network (MAN) metropolitan area such as city or town and handles bulk of communication activity across the region A MAN typically includes one or more LAN but covers a smaller geographic area than a WAN

Server : A server is a computer that provides services to clients and controls access to hardware, software and other resources

A client is a computer  that request services from a server computer.

On a client/server network, one computer act as a server Client/Server that provides services and the other computers (client) on the network request services from the server. A server is a computer that controls access to the hardware, software and other resources on the network and provides a centralized storage area for program. A client is a computer that request services from a server computer.

Peer-to-peer is a simple, inexpensive network that Peer-to-Peer typically connects fewer than 10 computers. All computers in the network have equal capabilities to use the resources (hardware, software, data and file) available on the network. With peer-to-peer networks, there is no central server.

 Internet

A means of connecting a computer to any other computer anywhere in the world via dedicated routers and servers. When two computers are connected over the Internet, they can send and receive all kinds of information such as text, graphics, voice, video, and computer programs.
No one owns Internet, although several organizations the world over collaborate in its functioning and development. The high-speed, fiber-optic cables (called backbones) through which the bulk of the Internet data travels are owned by telephone companies in their respective countries.

The Internet grew out of the Advanced Research Projects Agency's Wide Area Network (then called ARPANET) established by the US Department Of Defense in 1960s for collaboration in military research among business and government laboratories.
Later universities and other US institutions connected to it. This resulted in ARPANET growing beyond everyone's expectations and acquiring the name 'Internet.' The development of hypertext based technology (called World Wide web, WWW, or just the Web) provided means of displaying text, graphics, and animations, and easy search and navigation tools that triggered Internet's explosive worldwide growth.

IP( Internet Protocol) Addressing

Two most important functions in a data network are: To uniquely identify each host or computer or device participating in network. This is called addressing. To be able to connect and move data packets between any devices in a network. This is often called switching and routing by connecting devices to switches and routers respectively. An IP address and Subnet Mask are very basic entities of data network. What is an IP Address? An IP address is a 32 bit number like 11000000101010000000000100000001 in binary  or 3232235777 in decimal. So it is written in  4 parts like 11000000.10101000.00000001.00000001  in binary form and 192.168.1.1 in decimal form.  This way it is easier to understand. Now, a unique number is sufficient to identify each host in a network but that alone cannot help in reaching from one host to another. Imagine if every house in world had a unique number or some name, but no state, city and country info. Would it be possible to reach a particular house even if its number is known? So logically, addresses are made up of parts, like state, city, street and finally house number. Most of the parts of an address are common to many people, like people living at same street or city. Generally only the house number and name finally differentiates between any two similar addresses. Similarly in case of IP address, we logically partition an IP address in parts so that we can reach a computer from anywhere (yes, obviously if the route exists). Also not that logically partitioning an IP address is different than writing an IP address in 4 parts, that’s just a notation. So to keep things simple we generally divide an IP address in two logical parts. One is network part and the other is host part. Network part is like street, city, state which is shared by multiple IP addresses. Host part is like house number and name of the person. Both parts together uniquely identifies a host or computer. We can also partition an IP address in more than two parts Packet Switching: Packet switching is a digital network transmission process in which data is broken into suitably-sized pieces or blocks for fast and efficient transfer via different network devices. When a computer attempts to send a file to another computer, the file is broken into packets so that it can be sent across the network in the most efficient way. These packets are then routed by network devices to the destination TCP/IP, in full Transmission Control Protocol/Internet Protocol, standard Internet communications protocols that allow digital computers to communicate over long distances. The Internet is a packet-switched network, in which information is broken down into small packets, sent individually over many different routes at the same time, and then reassembled at the receiving end. TCP is the component that collects and reassembles the packets of data, while IP is responsible for making sure the packets are sent to the right destination. TCP/IP was developed in the 1970s and adopted as the protocol standard for ARPANET (the predecessor to the Internet) in 1983.