Explain Bandwidth and Data Transmission
Bandwidth is the amount of data that can be transmitted within a fixed time period. When data is sent over a computer network, it is broken into small chunks called packets. Each packet contains headers. A header is information added to each packet that contains the packet's source and destination. A header also contains information that describes how to put all the packets back together again at the destination. The size of the bandwidth determines the amount of information that can be transmitted.
Bandwidth is measured in bits per second and usually is denoted by any of the following units of measure:
■ kbps is kilobits per second.
■ Mbps is megabits per second. Note
1 byte is equal to 8 bits and is abbreviated with a capital B. 1 MBps is approximately 8 Mbps.
Figure 8-7 shows how bandwidth on a network can be compared to a highway. In this example, the cars and trucks represent the data. The number of lanes on the highway represents the number of cars that can travel on the highway at the same time. An eight-lane highway can handle four times the number of cars that a two-lane highway can.
Figure 8-7 Highway Analogy
The data that is transmitted over the network can flow using one of three modes: simplex, half duplex, or full duplex:
■ Simplex: Simplex, also called unidirectional, is a single one-way transmission. An example of simplex transmission is the signal that is sent from a TV station to your TV
■ Half duplex: When data flows in one direction at a time, this is known as half duplex. With half duplex, the communications channel allows alternating transmission in two directions, but not in both directions simultaneously. Two-way radios, such as police and emergency communications mobile radios, work with half-duplex transmissions. When you press the button on the microphone to transmit, you cannot hear the person on the other end. If people at both ends try to talk at the same time, neither transmission gets through.
■ Full duplex: When data flows in both directions at the same time, this is known as full duplex. Although the data flows in both directions, the bandwidth is measured in only one direction. A network cable with 100 Mbps in full-duplex mode has a bandwidth of 100 Mbps. A telephone conversation is an example of full-duplex communication. Both people can talk and be heard at the same time.
Full-duplex networking technology increases network performance because data can be sent and received at the same time. Broadband technology allows multiple signals to travel on the same wire simultaneously. Broadband technologies, such as digital subscriber line (DSL) and cable, operate in full-duplex mode. With a DSL connection, for example, users can download data to their computer and talk on the telephone at the same time.
Continue reading here: Describe IP Addressing
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