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Generic Cell Rate Algorithm
The generic cell rate algorithm (GCRA) is a leaky bucket-type scheduling algorithm for the network scheduler that is used in Asynchronous Transfer Mode (ATM) networks. It is used to measure the timing of cells on virtual channels (VCs) and or Virtual Paths (VPs) against bandwidth and jitter limits contained in a traffic contract for the VC or VP to which the cells belong. Cells that do not conform to the limits given by the traffic contract may then be re-timed (delayed) in traffic shaping, or may be dropped (discarded) or reduced in priority (demoted) in traffic policing. Nonconforming cells that are reduced in priority may then be dropped, in preference to higher priority cells, by downstream components in the network that are experiencing congestion. Alternatively they may reach their destination (VC or VP termination) if there is enough capacity for them, despite them being excess cells as far as the contract is concerned: see priority control. The GCRA is given as the referen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaky Bucket
The leaky bucket is an algorithm based on an analogy of how a bucket with a constant leak will overflow if either the average rate at which water is poured in exceeds the rate at which the bucket leaks or if more water than the capacity of the bucket is poured in all at once. It can be used to determine whether some sequence of discrete events conforms to defined limits on their average and peak rates or frequencies, e.g. to limit the actions associated with these events to these rates or delay them until they do conform to the rates. It may also be used to check conformance or limit to an average rate alone, i.e. remove any variation from the average. It is used in packet-switched computer networks and telecommunications networks in both the traffic policing, traffic shaping and scheduling of data transmissions, in the form of packets, to defined limits on bandwidth and burstiness (a measure of the variations in the traffic flow). A version of the leaky bucket, the gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ATM Forum
The ATM Forum was founded in 1991 to be the industry consortium to promote Asynchronous Transfer Mode technology used in telecommunication networks; the founding president and chairman was Fred Sammartino of Sun Microsystems. It was a non-profit international organization. The ATM Forum created over 200 implementation agreements. History In 1996 ATM technology stabilized with the "Anchorage Accord", which established the baseline of ATM implementations. While ATM did not live up to every expectation, it remained an important core network technology. The Frame Relay Forum (promoting Frame Relay) also started in 1991. The MPLS Forum (which supported Multiprotocol Label Switching had begun in 2000. Those two merged in 2003 to become the MPLS and Frame Relay Alliance (MFA). In 2005, the ATM Forum joined forces with the MFA to form the MFA Forum, which was renamed to be the IP/MPLS Forum. In May 2009 the IP/MPLS Forum merged with the Broadband Forum. Sampling of specifications * AT ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Token Bucket
The token bucket is an algorithm used in packet-switched and telecommunications networks. It can be used to check that data transmissions, in the form of packets, conform to defined limits on bandwidth and burstiness (a measure of the unevenness or variations in the traffic flow). It can also be used as a scheduling algorithm to determine the timing of transmissions that will comply with the limits set for the bandwidth and burstiness: see network scheduler. Overview The token bucket algorithm is based on an analogy of a fixed capacity bucket into which tokens, normally representing a unit of bytes or a single packet of predetermined size, are added at a fixed rate. When a packet is to be checked for conformance to the defined limits, the bucket is inspected to see if it contains sufficient tokens at that time. If so, the appropriate number of tokens, e.g. equivalent to the length of the packet in bytes, are removed ("cashed in"), and the packet is passed, e.g., for transmissio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Shaping
Traffic shaping is a bandwidth management technique used on computer networks which delays some or all datagrams to bring them into compliance with a desired ''traffic profile''. Traffic shaping is used to optimize or guarantee performance, improve latency, or increase usable bandwidth for some kinds of packets by delaying other kinds. It is often confused with traffic policing, the distinct but related practice of packet dropping and packet marking. The most common type of traffic shaping is application-based traffic shaping. In application-based traffic shaping, fingerprinting tools are first used to identify applications of interest, which are then subject to shaping policies. Some controversial cases of application-based traffic shaping include bandwidth throttling of peer-to-peer file sharing traffic. Many application protocols use encryption to circumvent application-based traffic shaping. Another type of traffic shaping is route-based traffic shaping. Route-based traffi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connection Admission Control
Connection may refer to: Mathematics *Connection (algebraic framework) *Connection (mathematics), a way of specifying a derivative of a geometrical object along a vector field on a manifold *Connection (affine bundle) * Connection (composite bundle) *Connection (fibred manifold) *Connection (principal bundle), gives the derivative of a section of a principal bundle *Connection (vector bundle), differentiates a section of a vector bundle along a vector field *Cartan connection, achieved by identifying tangent spaces with the tangent space of a certain model Klein geometry *Ehresmann connection, gives a manner for differentiating sections of a general fibre bundle *Electrical connection, allows the flow of electrons *Galois connection, a type of correspondence between two partially ordered sets *Affine connection, a geometric object on a smooth manifold which connects nearby tangent spaces *Levi-Civita connection, used in differential geometry and general relativity; differentiates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Contract
If a network service (or application) wishes to use a broadband network (an ATM network in particular) to transport a particular kind of traffic, it must first inform the network about what kind of traffic is to be transported, and the performance requirements of that traffic.Hiroshi Saito, Teletraffic Technologies in ATM Networks, Artech House, 1993. . The application presents this information to the network in the form of a traffic contract. The Traffic descriptor When a connection is requested by an application, the application indicates to the network:Ferguson P., Huston G., Quality of Service: Delivering QoS on the Internet and in Corporate Networks, John Wiley & Sons, Inc., 1998. . *The Type of Service required. *The Traffic Parameters of each data flow in both directions. *The quality of service (QoS) Parameters requested in each direction. These parameters form the ''traffic descriptor'' for the connection. Type of Service Currently, five ATM Forum-defined servic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaky Bucket
The leaky bucket is an algorithm based on an analogy of how a bucket with a constant leak will overflow if either the average rate at which water is poured in exceeds the rate at which the bucket leaks or if more water than the capacity of the bucket is poured in all at once. It can be used to determine whether some sequence of discrete events conforms to defined limits on their average and peak rates or frequencies, e.g. to limit the actions associated with these events to these rates or delay them until they do conform to the rates. It may also be used to check conformance or limit to an average rate alone, i.e. remove any variation from the average. It is used in packet-switched computer networks and telecommunications networks in both the traffic policing, traffic shaping and scheduling of data transmissions, in the form of packets, to defined limits on bandwidth and burstiness (a measure of the variations in the traffic flow). A version of the leaky bucket, the gener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dual LBC
Dual or Duals may refer to: Paired/two things * Dual (mathematics), a notion of paired concepts that mirror one another ** Dual (category theory), a formalization of mathematical duality *** see more cases in :Duality theories * Dual (grammatical number), a grammatical category used in some languages * Dual county, a Gaelic games county which in both Gaelic football and hurling * Dual diagnosis, a psychiatric diagnosis of co-occurrence of substance abuse and a mental problem * Dual fertilization, simultaneous application of a P-type and N-type fertilizer * Dual impedance, electrical circuits that are the dual of each other * Dual SIM cellphone supporting use of two SIMs * Aerochute International Dual a two-seat Australian powered parachute design Acronyms and other uses * Dual (brand), a manufacturer of Hifi equipment * DUAL (cognitive architecture), an artificial intelligence design model * DUAL algorithm, or diffusing update algorithm, used to update Internet protocol routing ta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variable Bit Rate
Variable bitrate (VBR) is a term used in telecommunications and computing that relates to the bitrate used in sound or video encoding. As opposed to constant bitrate (CBR), VBR files vary the amount of output data per time segment. VBR allows a higher bitrate (and therefore more storage space) to be allocated to the more complex segments of media files while less space is allocated to less complex segments. The average of these rates can be calculated to produce an average bitrate for the file. MP3, WMA and AAC audio files can optionally be encoded in VBR, while Opus and Vorbis are encoded in VBR by default. Variable bit rate encoding is also commonly used on MPEG-2 video, MPEG-4 Part 2 video (Xvid, DivX, etc.), MPEG-4 Part 10/H.264 video, Theora, Dirac and other video compression formats. Additionally, variable rate encoding is inherent in lossless compression schemes such as FLAC and Apple Lossless. Advantages and disadvantages of VBR The advantages of VBR are that it prod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Contract
If a network service (or application) wishes to use a broadband network (an ATM network in particular) to transport a particular kind of traffic, it must first inform the network about what kind of traffic is to be transported, and the performance requirements of that traffic.Hiroshi Saito, Teletraffic Technologies in ATM Networks, Artech House, 1993. . The application presents this information to the network in the form of a traffic contract. The Traffic descriptor When a connection is requested by an application, the application indicates to the network:Ferguson P., Huston G., Quality of Service: Delivering QoS on the Internet and in Corporate Networks, John Wiley & Sons, Inc., 1998. . *The Type of Service required. *The Traffic Parameters of each data flow in both directions. *The quality of service (QoS) Parameters requested in each direction. These parameters form the ''traffic descriptor'' for the connection. Type of Service Currently, five ATM Forum-defined servic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Policing (communications)
In communications, traffic policing is the process of monitoring network traffic for compliance with a traffic contract and taking steps to enforce that contract. Traffic sources which are aware of a traffic contract may apply traffic shaping to ensure their output stays within the contract and is thus not discarded. Traffic exceeding a traffic contract may be discarded immediately, marked as non-compliant, or left as-is, depending on administrative policy and the characteristics of the excess traffic. Effects The recipient of traffic that has been ''policed'' will observe packet loss distributed throughout periods when incoming traffic exceeded the contract. If the source does not limit its sending rate (for example, through a feedback mechanism), this will continue, and may appear to the recipient as if link errors or some other disruption is causing random packet loss. The received traffic, which has experienced policing en route, will typically comply with the contract, alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FPGA
A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware description language (HDL), similar to that used for an application-specific integrated circuit (ASIC). Circuit diagrams were previously used to specify the configuration, but this is increasingly rare due to the advent of electronic design automation tools. FPGAs contain an array of programmable logic blocks, and a hierarchy of reconfigurable interconnects allowing blocks to be wired together. Logic blocks can be configured to perform complex combinational functions, or act as simple logic gates like AND and XOR. In most FPGAs, logic blocks also include memory elements, which may be simple flip-flops or more complete blocks of memory. Many FPGAs can be reprogrammed to implement different logic functions, allowing flexible reconfigurabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
