Bandwidth (computing): Difference between revisions

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In [[computing]], '''bandwidth''' is the maximum rate of data transfer across a given path. Bandwidth may be characterized as '''network bandwidth''',<ref>[[Douglas Comer]], [https://books.google.com/books?id=tm-evHmOs3oC&dq=%22network+bandwidth%22+%22computer+networks%22&pg=PA99 Computer Networks and Internets], page 99 ff, Prentice Hall 2008.</ref> '''data bandwidth''',<ref>Fred Halsall, [https://books.google.com/books?id=HrXbAAAAMAAJ&q=%100data+bandwidth%100+Introduction to data+communications and computer networks], page 108, Addison-Wesley, 1985.</ref> or '''digital bandwidth'''.<ref>[https://books.google.com/books?id=7gqsZmr5HJcC&q=+0digital+bandwidth+0+%22 Cisco Networking Academy Program: CCNA 1 and 2 companion guide, Volym 1–2], Cisco Academy 2003</ref><ref>Behrouz A. Forouzan, ''Data communications and networking'', McGraw-Hill, 2007</ref>

This definition of ''bandwidth'' is in contrast to the field of [[signal processing]], [[wireless communications]], [[Modem|modem data transmission]], [[digital communications]], and [[electronics]],{{citation needed|date=January 2018}} in which ''bandwidth'' is used to refer to analogthe [[signal bandwidth]] measured in [[hertz]], meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the [[noise]] on the channel.

==Network capacity==

The term ''bandwidth'' sometimes defines the [[net bit rate]] ''peak bit rate'', ''information rate'', or physical layer ''useful bit rate'', [[channel capacity]], or the [[maximum throughput]] of a logical or physical communication path in a digital communication system. For example, [[bandwidth test]]s measure the maximum throughput of a computer network. The maximum rate that can be sustained on a link is limited by the [[Shannon–Hartley]] channel capacity for these communication systems, which is dependent on the [[bandwidth (signal processing)|bandwidth]] in hertz and the noise on the channel.

==Network consumption==

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== Web hosting ==

In [[Web hosting service]], the term ''bandwidth'' is often incorrectly used to describe the amount of data transferred to or from the website or server within a prescribed period of time, for example ''bandwidth consumption accumulated over a month'' measured in gigabytes per month.{{citation needed|date=November 2011}}<ref>{{Cite web |last=Low |first=Jerry |title=How Much Hosting Bandwidth Do I Need For My Website? |url=https://www.webhostingsecretrevealed.net/blog/web-hosting-guides/how-much-bandwidth-does-your-site-really-need/ |website=WHSR|date=27 March 2022 }}</ref> The more accurate phrase used for this meaning of a maximum amount of data transfer each month or given period is ''monthly data transfer''.{{Citation needed|date=May 2025}}

A similar situation can occur for end-user [[Internet service provider]]s as well, especially where network capacity is limited (for example in areas with underdeveloped internet connectivity and on wireless networks).

== Internet connections ==

*{{see [[also|List of interface bit rates]]|Bit rate#Progress trends}}

This table shows the maximum bandwidth (the physical layer net bit rate) of common Internet access technologies. For more detailed lists see

* [[List of interface bit rates]]

* {{slink|Bit rate|Progress trends}}

* {{slink|Bit rate|Multimedia}}

{| class="wikitable"

This table shows the maximum bandwidth (the|+Maximum physical layer net bit rate)bandwidth of common Internet access technologies. For more detailed lists see

!Bit rate

!Connection type

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{{Main|Edholm's law}}

[[Edholm's law]], proposed by and named after Phil Edholm in 2004,<ref name="Cherry">{{cite journal |last1=Cherry |first1=Steven |title=Edholm's law of bandwidth |journal=IEEE Spectrum |date=2004 |volume=41 |issue=7 |pages=58–60 |doi=10.1109/MSPEC.2004.1309810|s2cid=27580722 }}</ref> holds that the bandwidth of [[telecommunication network]]s double every 18 months, which has proven to be true since the 1970s.<ref name="Cherry"/><ref name=":1">{{Cite book|title=Time Multiplexed Beam-Forming with Space-Frequency Transformation|last1=Deng|first1=Wei|last2=Mahmoudi|first2=Reza|last3=van Roermund|first3=Arthur|publisher=Springer|year=2012|isbn=9781461450450|___location=New York|pages=1}}</ref> The trend is evident in the cases of [[Internet]],<ref name="Cherry"/> [[cellular network|cellular]] (mobile), [[wireless LAN]] and [[Personal area network|wireless personal area networks]].<ref name=":1" />

The [[MOSFET]] (metal–oxide–semiconductor field-effect transistor) is the most important factor enabling the rapid increase in bandwidth.<ref name="Jindal">{{cite book |last1=Jindal |first1=Renuka P. |title=2009 2nd International Workshop on Electron Devices and Semiconductor Technology |chapter=From millibits to terabits per second and beyond - over 60 years of innovation |date=2009 |pages=1–6 |doi=10.1109/EDST.2009.5166093 |chapter-url=https://events.vtools.ieee.org/m/195547|isbn=978-1-4244-3831-0 |s2cid=25112828 }}</ref> The MOSFET (MOS transistor) was invented by [[Mohamed M. Atalla]] and [[Dawon Kahng]] at [[Bell Labs]] in 1959,<ref name="computerhistory">{{cite journal|url=https://www.computerhistory.org/siliconengine/metal-oxide-semiconductor-mos-transistor-demonstrated/|title=1960 - Metal Oxide Semiconductor (MOS) Transistor Demonstrated|journal=The Silicon Engine|publisher=[[Computer History Museum]]}}</ref><ref name="Lojek">{{cite book |last1=Lojek |first1=Bo |title=History of Semiconductor Engineering |date=2007 |publisher=[[Springer Science & Business Media]] |isbn=9783540342588 |pages=321–3}}</ref><ref name="computerhistory-transistor">{{cite web |title=Who Invented the Transistor? |url=https://www.computerhistory.org/atchm/who-invented-the-transistor/ |website=[[Computer History Museum]] |date=4 December 2013 |access-date=20 July 2019}}</ref> and went on to become the basic building block of modern [[telecommunications]] technology.<ref name="triumph">{{cite web |title=Triumph of the MOS Transistor |url=https://www.youtube.com/watch?v=q6fBEjf9WPw | archive-url=https://ghostarchive.org/varchive/youtube/20211107/q6fBEjf9WPw| archive-date=2021-11-07 | url-status=live|website=[[YouTube]] |publisher=[[Computer History Museum]] |access-date=21 July 2019 |date=6 August 2010}}{{cbignore}}</ref><ref name="Raymer">{{cite book |last1=Raymer |first1=Michael G. |title=The Silicon Web: Physics for the Internet Age |date=2009 |publisher=[[CRC Press]] |isbn=9781439803127 |page=365 |url=https://books.google.com/books?id=PLYChGDqa6EC&pg=PA365}}</ref> Continuous [[MOSFET scaling]], along with various advances in MOS technology, has enabled both [[Moore's law]] ([[transistor count]]s in [[integrated circuit]] chips doubling every two years) and Edholm's law (communication bandwidth doubling every 18 months).<ref name="Jindal"/>