Cleanup laundry date March 2009 Bandwidthmanagement is the process of measuring and controlling the communications traffic, packets on a network link, to avoid filling the link to capacity or overfilling the link, which would result in network congestion and poor performance of the network. ManagementBandwidthmanagement mechanisms may be used to further engineer performance and includes Traffic shaping rate limiting Token bucket Leaky bucket TCP rate control artificially adjusting TCP window size ... ir library pdf DEC0202.pdf BandwidthManagement Tools, Strategies, and Issues http www.techsoupforlibraries.org cookbook 3 networking and security bandwidthmanagement TechSoup for Libraries BandwidthManagement http netequalizernews.com 2009 07 16 the true price of bandwidth monitoring The True Price of Bandwidth Monitoring DEFAULTSORT BandwidthManagement Category Network performance Internet ... traffic rate and burst size Explicit congestion notification Buffer tuning Bandwidth reservation ... when the network reaches capacity results in waste of bandwidth Burstiness of web traffic requires spare bandwidth to rapidly accommodate the bursty traffic Lack of widespread support for Network congestion avoidance IP ECN explicit congestion notification and Quality of Service management on the Internet ISPs Internet Service Provider s typically retain control over queue management and quality ... more bandwidth fairly Tools and techniques Packet sniffer s Network traffic measurement See also INASP runs bandwidthmanagement training workshops and produces reports Bandwidthmanagement using NetFlow and IPFIX data Network congestion avoidance lists some techniques for prevention and management of congestion on routers Traffic shaping and Rate limiting are bandwidthmanagement traffic control techniques Bandwidthmanagement is a subset of Network management and Performance management Network traffic measurement is a subset of Network monitoring Bandwidth throttling Bandwidth cap Notes ... more details
wiktionary Bandwidth has several related meanings Bandwidth signal processing or analog bandwidth , frequency bandwidth or radio bandwidth a measure of the width of a range of frequencies, measured in hertz Bandwidth computing or digital bandwidth a rate of data transfer, bit rate or throughput, measured in bits per second bps Spectral linewidth the width of an atomic or molecular spectral line, measured in hertz Bandwidth can also refer to Bandwidth linear algebra , the width of the non zero terms around the diagonal of a matrix In kernel density estimation , bandwidth describes the width of the convolution kernel used A normative expected range of linguistic behavior in language expectancy theory In list of buzzwords business jargon , the resources needed to complete a task or project Bandwidth radio program A Canadian radio program Graph bandwidth , in graph theory disambig ar da B ndbredde ... more details
path. This sense applies to expressions such as bandwidth shaping , bandwidthmanagement , bandwidth ...Other uses Bandwidth disambiguation Bandwidth Wiktionary Bandwidth In computer networking and computer science , bandwidth , ref Andrew S. Tanenbaum http books.google.com books?id Pd z64SJRBAC&printsec ...&sa X&oi book result&ct result&resnum 1&ved 0CC8Q6AEwAA v snippet&q bandwidth 20kbps&f false Computer networks , Prentice Hall PTR, 2003 ref network bandwidth , ref Douglas Comer , http books.google.com books?id tm evHmOs3oC&pg PA99&dq 22network bandwidth 22 22computer networks 22&hl en&ei mvqcTOHIMIb2tgPbnpXWAQ ... and Internets , page 99 ff, Prentice Hall 2008. ref data bandwidth , ref Fred Halsall , http books.google.com books?ei dvycTJ2BDoqosAOhu DVAQ&ct result&hl en&id HrXbAAAAMAAJ&dq 22data bandwidth 22 22computer networks 22&q 22data bandwidth 22 Introduction to data communications and computer networks , page 108, Addison Wesley, 1985. ref or digital bandwidth ref http books.google.com books?ei rfmcTPKEN5L6swOekeXVAQ&ct result&hl en&id 7gqsZmr5HJcC&dq 22digital bandwidth 22 22computer networks 22&q 22digital bandwidth 22 Cisco Networking Academy Program CCNA 1 and 2 companion guide, Volym 1 ... , digital communications , wireless communications , electronics , etc., bandwidth refers to analog signal bandwidth measured in hertz the original meaning of the term. 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. Network bandwidth capacity In computer networking, bandwidth ... communication path in a digital communication system. For example, bandwidth test s measure the maximum ... data rate of a physical communication link is proportional to its bandwidth signal processing bandwidth in hertz , which is sometimes called frequency bandwidth , spectral bandwidth , radio frequency RF bandwidth , signal bandwidth or analog bandwidth . Network bandwidth consumption In computer ... more details
Unreferenced date December 2006 Orphan date February 2009 In computing , equalization is a type of bandwidthmanagement that makes adjustments to the flow of data along a computer network . By adding Latency engineering latency to low priority tasks, it ensures high priority tasks receive sufficient bandwidth. DEFAULTSORT Equalization Computing Category Computer networks Compu network stub ... more details
See page 789 of Hennessy & Patterson cited below ... If the network is segmented into two equal parts, this is the bandwidth between the two parts. ref cite book author John L. Hennessy and David A. Patterson title Computer Architecture A Quantitative Approach edition Third Edition publisher Morgan Kaufmann Publishers, Inc date 2003 isbn 1558605967 ref Typically, this refers to the worst case segmentation, but being of equal parts is critical to the definition, as it refers to an actual bisection of the network. References references DEFAULTSORT Bisection Bandwidth Category Information theory Category Network management Compu network stub de Bisektionsbandbreite ... more details
Bandwidth cap Bandwidthmanagement Traffic shaping Rate limiting References Reflist Category Broadband ...refimprove date February 2011 Bandwidth throttling is a reactive measure employed in communication networks to regulate network traffic and minimize bandwidth congestion. Bandwidth throttling can occur ... bandwidth throttling to help limit network congestion and server crashes. On a broader level, the Internet Service Provider may use bandwidth throttling to help reduce a user s usage of bandwidth that is supplied ... out the usage of the total bandwidth supplied across all users on the network. Bandwidth throttling ... administrator may implement bandwidth throttling to control the number of requests a server responds to within a specified period of time. When a server using bandwidth throttling reaches the specified ... data structure queue to be processed once the bandwidth use reaches an acceptable level, but at peak ... away. Application A bandwidth intensive device, such as a server , might limit, or throttle ... that they engage in this practice, where they limit users bandwidth by up to 99 . ref http broadband.mpi ... their users bandwidth, with or without the user ever even realizing it. ref http netequalizernews.com 2009 03 21 analysis the white lies isps tell about broadband speeds ref Most commonly bandwidth throttling for users is done through the user s modem on the ISP level. Throttling vs. Capping Bandwidth throttling works by limiting throttling the rate at which a bandwidth intensive device a server ... as a bandwidth cap limits the transfer of a specified amount of data over a period of time. There are two types of bandwidth capping. A standard cap limits the bitrate or speed of data transfer on a broadband ... transmission capacity of the medium. A lowered cap reduces an individual user s bandwidth cap as a defensive measure and or as a punishment for heavy use of the medium s bandwidth . Sometimes this happens without notifying the user. The difference is that bandwidth throttling regulates a bandwidth ... more details
RFC 2638 from the IETF defines the entity of the Bandwidth Broker BB in the framework of DiffServ . According to RFC 2638, a Bandwidth Broker is an agent that has some knowledge of an organization s priorities and policies and allocates Quality of Service QoS resources with respect to those policies. In order to achieve an end to end allocation of resources across separate Domain Name System domain s, the Bandwidth Broker managing a Domain name domain will have to communicate with its adjacent peering ... agreements. Admission control is one of the main tasks that a Bandwidth Broker has to perform, in order to decide whether an incoming resource reservation request will be accepted or not. Most Bandwidth ... small and there is no need for buffer management resulting in low loss, low network delay delay and low Packet Delay Variation . Hence although loosely a BB allocates bandwidth, really it allocates carrier services i.e. QoS resources . Bandwidth Brokers can be configured with organizational policies ... in light of the policies and current allocation. Bandwidth Brokers only need to establish relationships ... of flow specifications in router s throughout an end to end path. In practical technical terms, the Bandwidth ... projects have developed or are developing Bandwidth Broker architectures http www staff.it.uts.edu.au ... http qbone.internet2.edu bb bboutline2.html QBone Bandwidth Broker Architecture http citeseer.ist.psu.edu sohail02survey.html The Survey of Bandwidth Broker http citeseer.ist.psu.edu clayton98internet.html ... QoS Control from Core Routers A Novel Bandwidth Broker Architecture for Scalable Support of Guaranteed ... for Bandwidth Brokers http citeseer.ist.psu.edu machiraju02scalable.html A Scalable and Robust Solution for Bandwidth Allocation http w3.tmit.bme.hu ips2004 papers ips2004 003.pdf Implementation of a Simple Bandwidth Broker for DiffServ Networks http www staff.it.uts.edu.au simmonds Papers QoS1.pdf Providing End to End guaranteed Quality of Service over the Internet A survey on Bandwidth Broker ... more details
Modal Bandwidth , in the discipline of telecommunications , refers to the signalling rate per distance unit. The signalling rate can typically be measured in MHz , and the modal bandwidth is expressed as MHz km multiplied . The Modal bandwidth of a multimode fiber is determined from the optical output power frequency spectrum. The frequency at which the amplitude drops three decibels dB relative to the zero frequency component of the fiber is defined as the 3 dB bandwidth or modal bandwidth of the fiber. Telecomm stub DEFAULTSORT Modal Bandwidth Category Telecommunications ... more details
more consumer friendly and fair. See also Bandwidth hogging BandwidthmanagementBandwidth throttling ...Primary sources date March 2009 A bandwidth cap , also known as a bit cap , limits the transfer of a specified .... Implementation of a Bandwidth computing bandwidth cap is sometimes termed a Fair Access Policy ... network bandwidth is relatively narrow. One type of bandwidth cap, administered by an Internet service .... The purpose of bandwidth capping is to prevent individual users from consuming the entire transmission ... charged that it is a method to charge consumers more by introducing tiered bandwidth caps Citation needed ... by ISP s. ref http www.rogers.com web content network management ref Sophistication is possible, and even required in limiting bandwidth. The simplest approach simply limits the data rate. The problem with the simplest approach is, a very active user could consume the maximum bandwidth continuously ... refers to the reported phenomenon of an ISP reducing an individual user s bandwidth cap, without ... traffic. Server computing Servers tend to use upstream bandwidth heavily, and violate most service ... bandwidth cap upon that user, and or restricts other services. e.g. NTT Communications in Japan ... Internet Service Providers in North America and Europe introduced bandwidth caps in the early ... data usage. Criticism of Usage based Billing in Canada Implementations of bandwidth limits and caps ... streaming media services such as Netflix , which uses large amounts of bandwidth to operate. ref ... of a strict bandwidth cap by a major ISP caused controversy in 2011 after the Canadian Radio ... a request by Bell Internet to begin enforcing a bandwidth cap legally known as usage based billing ... cable company Comcast offering 250GB of bandwidth a month , plus a 1 2 Canadian dollar CAD surcharge ... with unlimited bandwidth and thus congesting their network as most major Canadian ISP s do not offer ..., 5pm 10pm and not by any bandwidth hog heavy users alone. Full On February 2, 2011, Canadian Industry ... more details
In telecommunication , the term bandwidth compression has the following meanings The reduction of the Bandwidth computing bandwidth needed to transmit a given amount of data in a given time . The reduction of the time needed to transmit a given amount of data in a given bandwidth. Note Bandwidth compression implies a reduction in normal bandwidth of an information carrying signal information theory signal without reducing the information content of the signal. This can be accomplished with data compression techniques. Source from Federal Standard 1037C and from MIL STD 188 See also Modem Increasing speeds telecomm term stub Category Telecommunications terms ... more details
orphan date September 2009 nofootnotes date December 2009 Bandwidth pooling is used in network switch es to optimize the use of network resources . It allows switch processing cards to be shared by physical interface cards. This innovation frees switch resources that would otherwise be stranded when lower rate interface cards are deployed in an aggregation switch. Bandwidth Pooling in Dedicated Hosting This is a key mechanism for hosting buyers to determine which provider is offering the right pricing mechanism of bandwidth pricing. Most Dedicated Hosting providers bundle bandwidth pricing along with the monthly charge for the dedicated server. Let us illustrate this with the help of an example. An average 100 server from any of the common dedicated bandwidth providers would carry 2 TB of bandwidth. Suppose you purchased 10 servers then you would have the ability to consume 2 TB of bandwidth per server. However, let us assume that given your application architecture only 2 of these 10 servers are really web facing while the rest are used for storage, search, database or other internal functions then the provider that allows bandwidth pooling would let you consume overall 20 TB of bandwidth as incoming or outbound or both depending on their policy. The provider that does not offer Bandwidth pooling bandwidth pooling would just let you use 2 TB of bandwidth and the rest of the 8 TB of bandwidth would be practically unusable. Uses Bandwidth pooling is used in computer and mobile phone networks. References http www.faqs.org patents app 20090046740 Patent title Systems, methods and computer products for pooling of wireless collection bandwidth See also Bandwidth computing compu network stub DEFAULTSORT Bandwidth Pooling Category Electronics terms ... more details
A bandwidth hog is a derogatory term for a user of an internet connection who uses more Bandwidth computing bandwidth than other users on the network. ref http www.pcmag.com article2 0,2817,2339204,00.asp Is Comcast Discriminating Against VoIP Providers? PC magazine January 19, 2009, by Chloe Albanesius ref ISPs now refer to bandwidth hogs as heavy users in an attempt to avoid backlash by the public. Most ISPs bandwidth throttling throttle their customer s Internet connection 24 7 so bandwidth hog is virtually non existent from a transfer speed perspective. Bandwidth hog from a download upload cap perspective is incorrect due to an unlimited supply of data. External links http arstechnica.com tech policy news 2009 12 bandwidth hogs dont even exist says analyst.ars Bandwidth hogs join unicorns in realm of mythical creatures ArsTechnica.com http www.pcmag.com article2 0,2817,2368000,00.asp FCC Broadband Users Are Getting Half of What They Expect References reflist DEFAULTSORT Bandwidth Hogging Category Internet terminology Category File sharing internet stub ... more details
Unreferenced date December 2009 Orphan date December 2009 In signal processing , the essential bandwidth is the portion of a signal spectrum in the frequency domain which contains most of the energy of the signal. DEFAULTSORT Essential Bandwidth Category Signal processing telecomm stub ... more details
Bandwidth expansion is a technique for widening the Bandwidth signal processing bandwidth or the resonances in an Linear predictive coding LPC filter. This is done by moving all the Pole complex analysis poles towards the origin by a constant factor math gamma math . The bandwidth expanded filter math A z math can be easily derived from the original Digital filter filter math A z math by math A z A z gamma math Let math A z math be expressed as math A z sum k 0 N a kz k math The bandwidth expanded filter can be expressed as math A z sum k 0 N a k gamma kz k math In other words, each Linear prediction coefficient math a k math in the original filter is simply multiplied by math gamma k math in the bandwidth expanded filter. The simplicity of this transformation makes it attractive, especially in CELP coding of speech, where it is often used for the perceptual noise Weighting filter weighting and or to stabilize the LPC analysis. However, when it comes to stabilizing the LPC analysis, lag windowing is often preferred to bandwidth expansion. References P. Kabal, Ill Conditioning and Bandwidth Expansion in Linear Prediction of Speech , Proc. IEEE Int. Conf. Acoustics, Speech, Signal Processing , pp. I 824 I 827, 2003. Category Signal processing ... more details
Cleanup date December 2007 Unreferenced date May 2009 Coherence bandwidth is a statistical measurement of the range of frequencies over which the channel can be considered flat , or in other words the approximate maximum bandwidth or frequency interval over which two frequencies of a signal are likely to experience comparable or correlated amplitude fading . If the multipath time delay spread equals D second s, then the coherence bandwidth math W c math in rad s is given approximately by the equation math W c approx 2 pi over D math The coherence bandwidth varies over Cellular network cellular or PCS communications paths because the multipath spread D varies from path to path. Application Frequencies within a coherence bandwidth of one another tend to all fade in a similar or correlated fashion. One reason for designing the CDMA IS 95 waveform with a bandwidth of approximately 1.25 Megahertz MHz is because in many urban signaling environments the coherence bandwidth W sub c sub is significantly less than 1.25 MHz. Therefore, when fading occurs it occurs only over a relatively small fraction of the total CDMA signal bandwidth. The portion of the signal bandwidth over which fading does not occur typically contains enough signal power to sustain reliable communications.This is the bandwidth over which the channel transfer function remains virtually constant. Example If the delay spread D over a particular cellular communication path in an urban environment is 3 s, then using equation above, the coherence bandwidth is approximately 333 kilohertz kHz , which is only about 27 of the IS 95 bandwidth. See also Coherence time Coherence length Category Wave mechanics Category Radio frequency propagation ... more details
Citecheck date November 2007 Bandwidth optimization is one of many concerns webmasters deal with when hosting web content. Since most web hosts charge by Bandwidth computing bandwidth used or have an account limit on bandwidth, a prudent webmaster will squeeze and Bandwidth compression compress their files as much as possible without affecting the content s integrity. Lately, most web hosts are offering unlimited bandwidth. Reductions in bandwidth usage are measured in negabytes , a unit akin to other negative units such as negawatts , negavolts , negajoules , negameters , and negagrams . Even the simplest bandwidth optimization techniques can reduce bandwidth costs significantly. Owners of extremely high volume web services are especially diligent, and have been known to employ extreme techniques to save a few bytes per page. For example, many staple pages are highly optimized with whitespace and line breaks removed, unneeded quotes removed around HTML attributes, and images compressed to the limit while maintaining clarity. Most bandwidth optimization techniques can fit into one of three categories Efficiency, Compression, and Omission. Efficiency Efficiency techniques involve changing the web content in order to minimize the number of bytes that need to be sent. For example, use external files which will cache instead of inline styles and scripts, reuse icon images, use semantic markup. Fix any broken images, since these often send a verbose 404 error page. Compression Use compression on the server to squash files before they are sent. Compression is a well established technique in telecommunications, since without significant bandwidth compression, the telephone grid could not handle the amount of data that passes through it. On the web the most popular compression algorithm for real time compression is gzip . The topic of compression also includes image compression e.g. JPG, PNG, GIF Also see Wan optimization WAN Optimization Omission Omit unneeded bytes. Remove ... more details
The power bandwidth of an amplifier is sometimes taken as the frequency range or, rarely, the upper frequency limit for which the rated power output ref Audio Power Amplifier Design Handbook by Douglas Self page 22 ref of an amplifier can be maintained without excessive distortion to at least half of the full rated power. ref http www.answers.com topic power bandwidth ref ref The sound reinforcement handbook By Gary Davis, Ralph Jones page 197 ref Some specifications may mandate 100 of the rated power sometimes referring to the full power bandwidth . It should not be confused with half power bandwidth only used in conjunction with filter frequency response curves. Operational amplifiers often use the term full power bandwidth to refer to the frequency limit for the peak output voltage rather than power remaining up to the limit given for Direct current DC output voltage capability. Specifying power bandwidth Power bandwidth may be specified as a frequency range or as a graph. ref http www.nxp.com documents data sheet TDA1013B.pdf TDA1013B power amplifier IC specifications ref References reflist Category Sound Category Waves Physics stub ... more details
Commercial bandwidth is a term for the regular capacity of the telephone network required for intelligible speech. It was defined as 300 hertz to 3,400 hertz, although the modern PSTN is theoretically capable of transmitting from 0 Hz to 7,000 Hz using ISDN ref http tools.ietf.org html draft ietf isdnmib snmp isdn mib 01 multi user ISDN ref . References reflist See also DS0 Bandwidth signal processing voiceband telecomm stub Category Telephony ... more details
Bandwidth extension of Signal electrical engineering signal is defined as the deliberate process of expanding the frequency range Bandwidth signal processing bandwidth of a signal in which it contains an appreciable and useful content, and or the frequency range in which its effects are such. Its significant advancement in recent years has led to the technology being adopted commercially in several areas including Psychoacoustics psychacoustic bass enhancement of small loudspeaker s and the high frequency enhancement of coded speech and audio. Bandwidth extension has been used in both speech and audio compression applications. The algorithms used in G.729.1 and Spectral Band Replication SBR are two of many examples of bandwidth extension algorithms currently in use. In these methods, the low band of the spectrum is encoded using an existing codec, whereas the high band is coarsely parameterized using fewer parameters. Many of these bandwidth extension algorithms make use of the correlation between the low band and the high band in order to predict the wider band signal from extracted .... Bandwidth Extension of Speech in telephone systems Telephone speech signals are usually very degraded in quality. Part of this degradation is due to the limited bandwidth used in the telephone systems. In most systems frequencies lower than 250 Hz are cut and bandwidth only extends to frequencies ... using high pass filters and generating harmonics extends high frequency bandwidth. The generation .... The sparse information available in the small bandwidth will probably be too limited to extract a proper envelope. Bandwidth Extension of Audio Spectral band replication SBR is a new technique that has ... bandwidth extension, Convention Paper 5921 Presented at the Audio Engineering Society AES 115th ... and A. Spanias A Scalable Bandwidth Extension Algorithm Proceedings of IEEE International Conference ... Theory, September 2001, pp. 331 336. M. Nilsson and W. Kleijn, Avoiding over estimation in bandwidth ... more details
Unreferenced stub auto yes date December 2009 Bandwidth allocation refers to how Radio frequency radio frequencies are assigned to different applications. The radio spectrum is a finite resource creating the need for an effective allocation process. In the United States the Federal Communications Commission or Federal Communications Commission FCC has the responsibility allocating the portions of the spectrum, or bands to various industries. For example, the FCC shifted the location of television on the spectrum, to open up more space for mobile applications. ref http www.businessweek.com magazine content 07 53 b4065000572464.htm?chan ma Just Ahead A Wider Wireless World , Wildstrom, S. ,BusinessWeek,12 19 2007,Retrieved February 9, 2011 ref Different bands of spectrum are able to transmit more data than others, and some bands of the spectrum transmit clearer than others. Ref Mobile and Wireless Communications, Gow G.& Smith R. ,Open University Press, 2006 ref These bands are of critical importance for companies that intend to operate a business involving wireless communications. One method used to assign bands to users is auctions. Some economists believe based off Auction Theory auction theory , auctions are the most efficient method of allocating resources. Due to the differences in the amount of data each band can transmit and the clarity of the signal, auctions allow the more desirable bands to sell for more. ref Putting Economics above Ideology, Hazlett, T ,Barrons, July ... would violate one of the principles of the FCC, to protect the public interest. Bandwidth allocation can also be used in reference to the computing industry, in scenarios such as allocating Bandwidth computing bandwidth to a web site running on a server computing server , or allocating bandwidth to a computer ... by terminating or temporarily suspending access once the allocated bandwidth has been utilized. Setting ... reflist DEFAULTSORT Bandwidth Allocation Category Electronics terms Category Article Feedback ... more details
In graph theory , the graph bandwidth problem is stated as follows. For a graph G it is to label its n vertices v sub i sub with distinct integers f v sub i sub so that the quantity math max f v i f v j math is minimized over all edges math v i,v j math of G harv Chinn Chv talov Dewdney Gibbs 1982 . The problem ... , linear graph layout or linear graph placement . ref name feige The weighted graph bandwidth ... bandwidth is the bandwidth matrix theory bandwidth of a symmetric matrix which is the adjacency matrix of the graph. Bandwidth formulas for some graphs For several families of graphs math G math , the bandwidth math varphi G math is given by an explicit formula. The bandwidth of a path graph math ... K k,1 math on k 1 vertices has bandwidth math varphi S k lfloor k 1 2 rfloor 1 math . For the hypercube graph math Q n math on math 2 n math vertices the bandwidth was determined by harvtxt Harper 1966 ... of a product of two paths. J. Chvat lov , Discrete Mathematics 11 , 249&ndash 253, 1975. ref that the bandwidth ... n math vertices, is equal to math min m,n math . Bounds The bandwidth of a graph can be bounded in terms ... , a structurally very simple example of a tree graph theory tree , has comparatively large bandwidth ... log Delta n math . Computing the bandwidth Both the unweighted and weighted versions are special cases of the quadratic bottleneck assignment problem . The bandwidth problem is NP hard , even for some ... s, it is known that the bandwidth is hardness of approximation NP hard to approximate within any ... name feige Coping with the NP Hardness of the Graph Bandwidth Problem , Uriel Feige, Lecture Notes ... algorithm for obtaining linear graph layouts of low bandwidth is the Cuthill McKee algorithm . Applications ... to find approximate solutions for the graph bandwidth problem. Another application domain is in electronic ..., graph bandwidth problem models the problem of placement of a set of standard cells in a singe row ... viggo wwwcompendium node53.html Minimum bandwidth problem , in Pierluigi Crescenzi and Viggo ... more details
Memory bandwidth is the rate at which data can be read from or stored into a semiconductor memory by a central processing unit processor . Memory bandwidth is usually expressed in units of bytes per second bytes second , though this can vary for systems with natural data sizes that are not a multiple of the commonly used 8 bit bytes. Memory bandwidth that is advertised for a given memory or system is usually the maximum theoretical bandwidth. In practice the observed memory bandwidth will be less than and is guaranteed not to exceed the advertised bandwidth. A variety of Computer benchmark computer benchmarks exist to measure sustained memory bandwidth using a variety of access patterns. These are intended to provide insight into the memory bandwidth that a system should sustain on various classes of real applications. Conventions Perhaps surprisingly, there are at least three different conventions for counting the quantity of data transferred in the numerator of bytes per second bytes second , as discussed in more detail in ref STREAM Benchmark FAQ Counting Bytes and FLOPS http www.cs.virginia.edu ... copy example, the STREAM bandwidth would be counted as 1 million bytes read plus 1 million bytes ... by the user code or not. Using the same 1 million byte copy example, the hardware bandwidth on computer ... of misleading comparisons of bandwidth based on different amounts of data traffic performed. Computation Theoretical maximum memory bandwidth is typically computed by multiplying the width of the interface ... i.e., the throughput may be less than the theoretical maximum memory bandwidth . The nomenclature ... MHz , would have a theoretical maximum memory bandwidth of 400 million hertz 2 interfaces 64 lines ... which reflects the theoretical maximum bandwidth in mebibytes per second. So with this in mind, the above ... than 64 bits is not counted in the bandwidth computations, as neither the extra memory nor the extra bandwidth is available for user data. See also List of device bandwidths A major factors in real ... more details
The Bandwidth Allocation Protocol , along with its control protocol, the Bandwidth Allocation Control Protocol, is used to add and remove links in a multilink bundle over PPP, and specifying which peer is responsible for making decisions regarding bandwidthmanagement. The protocol was originally conceived by Craig Richards and Kevin Smith of Shiva Corporation and Ascend Communications respectively in 1997 ref http www.ietf.org rfc rfc2125.txt ref and has since been implemented on a number of routers, including in Cisco IOS ref http www.cisco.com univercd cc td doc product software ios112 pppbacp.htm Bandwidth Allocation Control Protocol Bot generated title ref . References references DEFAULTSORT Bandwidth Allocation Protocol Category Network protocols compu network stub ... more details
Unreferenced date December 2009 A bandwidth limited pulse also known as Fourier transform limited pulse , or more commonly, transform limited pulse is a pulse of a wave that has the minimum possible duration for a given power spectrum spectral Bandwidth signal processing bandwidth . Optics Optical pulses of this type can be generated by modelocking mode locked laser s. Bandwidth limited pulses have a constant phase waves phase across all frequencies making up the pulse. Any waveform can be disassembled into its spectral component s by Fourier analysis or Fourier transform ation. The length of a pulse thereby is determined by its complex spectral components, which include not just their relative intensities, but also the relative positions spectral phase of these spectral components. A bandwidth limited pulse can only be kept together if the dispersion optics dispersion of the medium the wave is travelling through is zero otherwise dispersion management is needed to revert the effects of unwanted spectral phase changes. Keeping pulses bandwidth limited is necessary to compress information in time or to achieve high field densities, as with ultrashort pulse s in Kerr lens modelocking modelocked lasers . DEFAULTSORT Bandwidth Limited Pulse Category Optics Category Nonlinear optics Category Laser science ... more details
Expert subject Telecommunications date November 2008 Unreferenced date February 2008 Dynamic bandwidth allocation is a technique by which traffic bandwidth in a shared telecommunications medium can be allocated on demand and fairly between different users of that bandwidth. This is a form of bandwidthmanagement , and is essentially the same thing as statistical multiplexing . Where the sharing of a link adapts in some way to the instantaneous traffic demands of the nodes connected to the link. Dynamic bandwidth allocation takes advantage of several attributes of shared networks 1 all users are typically not connected to the network at one time 2 even when connected, users are not transmitting data or voice or video at all times 3 most traffic is bursty there are gaps between packets of information that can be filled with other user traffic Different network protocols implement dynamic bandwidth allocation in different ways. These methods are typically defined in Standardization standard s developed by standards bodies such as the ITU , IEEE , FSAN , or IETF . One example is defined in the ITU G.983 specification for passive optical network PON . See also Statistical multiplexing Channel access method Time division duplex TDD Bandwidth Controller Dynamic TDMA Reservation ALOHA R ALOHA Packet reservation multiple access PRMA OFDMA CDMA Dynamic channel allocation Interleaved polling with adaptive cycle time IPACT Bandwidth guaranteed polling BGP Fair Queuing with Service Envelopes FQSE Limited Allocation with Excess Redistribution LAER EA Hybrid granting Modified Token bucket Channel access methods Category Telecommunications Category Computer networking Category Radio resource management ... more details
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