by Dinesh Thakur Category: Computer Network

In "frequency shift keying (FSK)", the frequency of a sinusoidal carrier is shifted between two discrete values. One of these frequencies (f1) represents a binary "1" and the other value (f0) represents a binary "0". The representation of digital data using FSK is as shown in Fig. Note that there is no change in the amplitude of the carrier.

 
by Dinesh Thakur Category: Computer Network

                   Point-to-point Connections

The point-to-point scheme provides separate communication channels for each pair of computers. When more than two computers need to communicate with one another, the number of connections grows very quickly as number of computer increases. Above figure illustrates that two computers need only one connection, three computers need three connections and four computers need six connections.



 
by Dinesh Thakur Category: Computer Network

Modem word came from the combination of two words modulator and demodulator.A modem is a hardware device that enables the computers to transmit data over cable or satellite connection.A modem converts signals between modulator and demodulator vice versa. The outgoing digital signals from a computer a modem can modulates to an analog signals and in the demodulation in reverse analog signal are converts back to a digital signal.The modems can be classified according to their characteristics as below:



 
by Dinesh Thakur Category: Computer Network

 Computer System Model

The term computer networks resulted from the 'combination of two major areas, namely computers and communications.



 
by Dinesh Thakur Category: Computer Network

A Metropolitan Area Network (MAN) covers larger geographic area such as cities or districts. By interconnecting smaller networks within a large geographic area, information is easily disseminated throughout the network. Local libraries and government agencies often use a MAN to connect to citizens and private industries. It may also connect MANs together within a larger area than LAN. The geographical limit of a MAN may span a city.



 
by Dinesh Thakur Category: Computer Network

• Hybrid networks are the networks that are based on both peer-to-peer & client-server relationship.
• Hybrid networks incorporate the best features of workgroups in peer-to-peer networks with the performance, security and reliability of server-based networks.
• Hybrid networks still provide all of the centralized services of servers, but they also allow users to share and manage their own resources within the workgroup.

 
by Dinesh Thakur Category: Computer Network

Broadcast: Any form of communication in which a single sender transmits messages to many receivers at once, the most familiar examples being the television and public radio systems. The opposite of broadcast is POINT-TO-POINT or narrowcast communication, between just a single transmitter and a single receiver - a telephone conversation for example. When such a multiple connection is made via a network cable as opposed to wireless, such communication is often called MULTIPOINT, as opposed to a point-to-point or UNICAST. Communication channel is shared by all the machines on the network in broadcast network.

 
by Dinesh Thakur Category: Computer Network

     Need For Computer Networks

The term network is defined as a set of computers of different types, terminals, telephones, and other communication equipments, connected by data communication links, which allow the network components to work together. The network components may be located within a small area or spread over many remote locations. In any case, data communications hold the network together.

 
by Dinesh Thakur Category: Computer Network

baud, baud rate A baud is the number of signaling elements per second sent by a communications device such as a modem, In theory, a modem with a high baud rate means fast transmission. The baud rate is therefore equal to the bit rate only if each signal element represents one bit of information.



 
by Dinesh Thakur Category: Computer Network

Client Computer: A personal computer in networking that connects to the server and uses the network services to perform user's tasks is a client computer.



 
by Dinesh Thakur Category: Computer Network

In computer networking Switches (also called switching hub, bridging hub,and more correctly called a network switch) and Bridges are the layer 2 computer networking devices. Once the number of users began to push the limits of a single computer network segment, there was a need to create a new segment to link two computer networks together a device called bridges accomplished this. basically the bridges have 2 ports, one for each computer networks, bridges actually inspect the data that passes through them and make decisions about whether to send it to the other computer network or not. Switch takes data from one network device and forwards it to the destination node based on MAC address.



 
by Dinesh Thakur Category: Computer Network

The distinguishing feature of star topology is that all nodes are joined at a single point, as shown in Figure. This single point is called as a central node, hub, or switch, to which all other devices are attached directly, generally via UTP or STP. This topology is frequently used for networks in which control of the network is located in the central node. This method is optimal when the bulk of communication is between the central and outlying nodes. If traffic is high between outlying nodes, an undue switching burden is placed on the central node.

 
by Dinesh Thakur Category: Computer Network

TCP/IP encapsulate upper layers using headers for the purpose of exchanging control and status information about the progress of the communication because its protocols also engage in peer talk by encapsulating data with protocol headers before submitting it to the underlying layer for subsequent delivery to the network. The data communication using TCP/IP and Ethernet as it is passed down the layers by an application on node X to node Y across the network.



 
by Dinesh Thakur Category: Computer Network

A Distributed computing is a model of computation that is firmly related to Distributed Systems, refers to as multiple computer systems located at different places linked together over a network and use to solve higher level computation without having to use an expensive supercomputer. Distributed system is called, When collection of various computers seems a single coherent system to its client, then it is called distributed system.



 
by Dinesh Thakur Category: Computer Network

  Bus Topology

Bus topologies are multipoint electrical circuits that can be implemented using coaxial cable, UTP, or STP. Data transmission is bidirectional, with the attached devices transmitting in both directions. While generally operating at a raw data rate of 10 Mbps, actual throughput is much less.

 
by Dinesh Thakur Category: Computer Network

To access Internet Through a Cable TV. Computer Network requires a cable Modem. It has two interfaces on it one for computer  and other for Cable Network The Computer side interface is usually is a USB Interface or 10Mbps Ethernet And The Cable Network is common cable wire interface.

 
by Dinesh Thakur Category: Computer Network

A LAN Operating System, or Network Operating System (NOS), is software that provides the network with multi-user, multitasking capabilities. The operating system facilitates communications and resource sharing, thereby providing the basic framework for the operation of the LAN. The operating system consists of modules that are distributed throughout the LAN environment. Some NOS modules reside in servers, while other modules reside in the clients.



 
by Dinesh Thakur Category: Computer Network

Connectionless service is a self-contained action and does not include establishment, maintenance and releasing a connection.

• Each message carries the full destination address and is treated and routed independently of all other messages.

 
by Dinesh Thakur Category: Computer Network

A packet is the unit of data that is routed between an origin of computer or device to another on the Internet or any other packet-switched network. When any file (e-mail message, HTML file, Graphics Interchange Format file, Uniform Resource Locator request, and so forth) is sent from one place of network to another place of network on the Internet, the Transmission Control Protocol (TCP) layer of TCP/IP of network.



 
by Dinesh Thakur Category: Computer Network

Amplitude Shift Keying (ASK) is the simplest type of digital CW modulation. Here the carrier is a sinewave of frequency fc. We can represent the carrier signal mathematically as follows:

 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.