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Bandwidth Related Entries Web Links New/Updated Information Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM. Bandwidth is the information-carrying capacity of a communication channel. The channel may be analog or digital. Analog transmissions such as telephone calls, AM and FM radio, and television are measured in cycles per second (hertz or Hz). Digital transmissions are measured in bits per second. For digital systems, the terms "bandwidth" and "capacity" are often used interchangeably, and the actual transmission capabilities are referred to as the data transfer rate (or just data rate). This topic continues in "The Encyclopedia of Networking and Telecommunications" with a discussion of the following:
Refer to the related entries page for other topics, including bandwidth management, throughput, prioritization of network traffic, QoS (quality of service), policy-based management, and traffic management and shaping. The following RFCs provide interesting information about bandwidth utilization on TCP/IP Networks:
Bandwidth Requirements and Ratings In the United States, the Federal Communications Commission (FCC) is in charge of allocating the electromagnetic spectrum and, thus, the bandwidth of various communication systems. In the electromagnetic spectrum, sound waves occupy low ranges, while microwaves, visible light, ultraviolet, and X-rays occupy upper ranges. The bandwidths occupied by various communication technologies are described in "Electromagnetic Spectrum." The bandwidth requirements of various applications are listed in Table Bandwidth-1. The rates are shown in bits/sec (bits per second), Kbits/sec (thousands of bits per second), Mbits/sec (millions of bits per second), and Gbits/sec (billions of bits per second). Compression and other techniques can reduce these requirements.
Table Bandwidth-1: Bandwidth requirements for various applications The transmission rates of various communication systems are listed in Table Bandwidth-2. Compression techniques and signal encoding are used to boost data rates. For example, modems use the ITU V.42 bis data compression standard to compress data at a ratio of over 3 to 1. V.42 bis compresses and decompresses on the fly as data is sent and received by connected modems.
Table Bandwidth-2: Transmission rates of various communication systems Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia. |