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Sunday 26 June 2011

Communication and Network.

Modulation.










Modulation refers to the process of varying one or more properties of a high-frequency periodic waveform called the carrier signal, with a modulating signal which typically contains information to be transmitted. Similarly, modulation occurs in a musical instrument by varying its volume, timing and pitch. The purpose of modulation is usually to enable the carrier signal to transport the information in the modulation signal to some destination.
A device that does modulation is known as a modulator and a device that performs the inverse operation of modulation is known as a demodulator. The one that does both is called a modem.

Demodulation.




 Demodulation is the act of extracting the original information-bearing signal from a modulated carrier wave. A demodulator is an electronic circuit usually a computer program that is used to recover the information content from the modulated wave itself
 Once again, another common one is in a modem, which is a contraction of the term like demodulator.

Bandwidth.




Digital bandwidth defines the rate of data transferred which is measured in bits per second (bps). There are lots of other terms pertaining to this. Such like network bandwidth, data bandwidth, or digital bandwidth. They can also be measured in kilobits/s, megabits/s etc Some computer networking authors prefer less ambiguous terms such as bit rate, channel capacity and  throughput rather than bandwidth in bit/s, to avoid this confusion

Internet protocol.





The Internet Protocol Suite is the set of communication protocols used for the internet and other similar networks. It is commonly also known as TCP/IP which stands for  Transmission control protocol (TCP) and the internet protocol (IP)the first two networking protocols defined in this standard. Modern IP networking represents a synthesis of several developments that began to evolve in the 1960s and 1970s, namely the internet and LAN , which started during the 1980s, together with the creation of the world wide web 10 years after.





Node.








A node is a communication point, connection point  or either  a redistribution point.It depends on the network and protocol layer related to it. A physical network node ,an active electronic device is attached to a network which makes it capable of sending, receiving, or forwarding information over a communications channel. A passive distribution point such as a distribution frame or patch panel is consequently not a node.
In network theory or graph theory, the term node refers to a point in a network topology at which lines intersect or branch out.

Client.


A client is an application or system that accesses a remote service on another computer system, known as a server, through a given network.  Increasingly, existing large client applications are being switched to websites, making the browser a sort of universal client. This avoids the hassle of downloading a large piece of software onto any computer you want to use the application on. An example is the increase usage of web-mail. Make it be pc’s or workstations, the difference between client and server operating system is just another way of marketing. The server version may have more OS components, allow more simultaneous logins, but can be pricy, while the client version may contain more end-user software.


Network Server.



network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet. There are different types of servers; such includes Web servers, proxy servers, and FTP servers.
Servers are often up to their jobs, meaning that they perform no other tasks besides their server tasks. Moreover, on multiprocessing operating systems, however, a single computer can finish several programs at once. A server in this case could refer to the program that is managing resources rather than the entire computer. It saves time for both the user and the computer.


Network Administrator.


network administrator is a person responsible for the maintenance of computer hardware and software that comprises a computer network. Usually, they perform tasks like deploying, configuring, maintaining and monitoring active network equipment.
The network administrator is usually the level of technical/network staff in an organization and will rarely be involved with direct user support; meaning to say is their best friend is their computers. The network administrator will concentrate on the overall performance of the network, server deployment and security.


Network operating system.


Dialoguer or a networking operating system (NOS) is a program that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions. The system’s purpose is to allow shared file and printer access among multiple computers in a network, typically a local area network (LAN), a private network or to other networks. Some examples of popular NOS are  Microsoft Windows Server 2003Microsoft Windows Server 2008UNIX, Linux, Mac and Novell NetWare.