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Network Scheduler
A network scheduler, also called packet scheduler, queueing discipline (qdisc) or queueing algorithm, is an arbiter on a node in a packet switching communication network. It manages the sequence of network packets in the transmit and receive queues of the protocol stack and network interface controller. There are several network schedulers available for the different operating systems, that implement many of the existing network scheduling algorithms. The network scheduler logic decides which network packet to forward next. The network scheduler is associated with a queuing system, storing the network packets temporarily until they are transmitted. Systems may have a single or multiple queues in which case each may hold the packets of one flow, classification, or priority. In some cases it may not be possible to schedule all transmissions within the constraints of the system. In these cases the network scheduler is responsible for deciding which traffic to forward and what get ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Queue
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted. A datum is an individual value in a collection of data. Data is usually organized into structures such as tables that provide additional context and meaning, and which may themselves be used as data in larger structures. Data may be used as variables in a computational process. Data may represent abstract ideas or concrete measurements. Data is commonly used in scientific research, economics, and in virtually every other form of human organizational activity. Examples of data sets include price indices (such as consumer price index), unemployment rates, literacy rates, and census data. In this context, data represents the raw facts and figures which can be used in such a manner in order to capture the useful information out of it. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Of Service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc. In the field of computer networking and other packet-switched telecommunication networks, quality of service refers to traffic prioritization and resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priorities to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. Quality of service is particularly important for the transport of traffic with special requirements. In particular, developers have introduced Vo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kernel
Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learning * Kernelization, a technique for designing efficient algorithms ** Kernel, a routine that is executed in a vectorized loop, for example in general-purpose computing on graphics processing units * KERNAL, the Commodore operating system Mathematics Objects * Kernel (algebra), a general concept that includes: ** Kernel (linear algebra) or null space, a set of vectors mapped to the zero vector ** Kernel (category theory), a generalization of the kernel of a homomorphism ** Kernel (set theory), an equivalence relation: partition by image under a function ** Difference kernel, a binary equalizer: the kernel of the difference of two functions Functions * Kernel (geometry), the set of points within a polygon from which the whole polygon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Kernel
The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU operating system, which was written to be a free (libre) replacement for Unix. Linux is provided under the GNU General Public License version 2 only, but it contains files under other compatible licenses. Since the late 1990s, it has been included as part of a large number of operating system distributions, many of which are commonly also called Linux. Linux is deployed on a wide variety of computing systems, such as embedded devices, mobile devices (including its use in the Android operating system), personal computers, servers, mainframes, and supercomputers. It can be tailored for specific architectures and for several usage scenarios using a family of simple commands (that is, without the need of manually editing its source c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deficit Round Robin
Deficit Round Robin (DRR), also Deficit Weighted Round Robin (DWRR), is a scheduling algorithm for the network scheduler. DRR is, like weighted fair queuing (WFQ), a packet-based implementation of the ideal Generalized Processor Sharing (GPS) policy. It was proposed by M. Shreedhar and G. Varghese in 1995 as an efficient (with ''O(1)'' complexity) and fair algorithm. Details In DRR, a scheduler handling N flows is configured with one quantum Q_i for each flow. This global idea is that, at each round, the flow i can send at most Q_i bytes, and the remaining, if any, is reported to the next round. In this way, the flow of number will achieve a minimal long term data rate of \fracR, where R is the link rate. Algorithm The DRR scans all non-empty queues in sequence. When a non-empty queue i is selected, its deficit counter is incremented by its quantum value. Then, the value of the deficit counter is a maximal number of bytes that can be sent at this turn: if the deficit counter i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Credit-based Fair Queuing
Credit-based fair queuing is a computationally efficient alternative to fair queueing. Credit is accumulated to queues as they wait for service. Credit is spent by queues while they are being serviced. Queues with positive credit are eligible for service. The rate of credit accumulation and release can be adjusted on a queue-by-queue basis to produce a weighted queuing behavior. Credit-based queuing is used in Resilient Packet Ring networks and in the IEEE 802.1Qav component of Audio Video Bridging and its successor, Time Sensitive Networking. In IEEE 802.1Qav, it is called Credit Based Shaper (CBS). See also * Max-min fairness * Scheduling (computing) * Weighted fair queuing Weighted fair queueing (WFQ) is a network scheduling algorithm. WFQ is both a packet-based implementation of the generalized processor sharing (GPS) policy, and a natural extension of fair queuing (FQ). Whereas FQ shares the link's capacity in ... References * *Bensaou, Brahim; Tsang, Danny H. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAKE (queue Management Algorithm)
Cake is a flour confection made from flour, sugar, and other ingredients, and is usually baked. In their oldest forms, cakes were modifications of bread, but cakes now cover a wide range of preparations that can be simple or elaborate, and which share features with desserts such as pastries, meringues, custards, and pies. The most common ingredients include flour, sugar, eggs, fat (such as butter, oil or margarine), a liquid, and a leavening agent, such as baking soda or baking powder. Common additional ingredients include dried, candied, or fresh fruit, nuts, cocoa, and extracts such as vanilla, with numerous substitutions for the primary ingredients. Cakes can also be filled with fruit preserves, nuts or dessert sauces (like custard, jelly, cooked fruit, whipped cream or syrups), iced with buttercream or other icings, and decorated with marzipan, piped borders, or candied fruit. Cake is often served as a celebratory dish on ceremonial occasions, such as w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CoDel
CoDel (''Controlled Delay''; pronounced "coddle") is an active queue management (AQM) algorithm in network routing, developed by Van Jacobson and Kathleen Nichols and published as RFC8289. It is designed to overcome bufferbloat in networking hardware, such as routers, by setting limits on the delay network packets experience as they pass through buffers in this equipment. CoDel aims to improve on the overall performance of the random early detection (RED) algorithm by addressing some of its fundamental misconceptions, as perceived by Jacobson, and by being easier to manage. In 2012, an implementation of CoDel was written by Dave Täht and Eric Dumazet for the Linux kernel and dual licensed under the GNU General Public License and the 3-clause BSD license. Dumazet's improvement on CoDel is called FQ-CoDel, standing for "Fair/Flow Queue CoDel"; it was first adopted as the standard AQM and packet scheduling solution in 2014 in the OpenWrt 14.07 release called "Barrier Breaker". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class-based Queueing
Class-based queuing (CBQ) is a queuing discipline for the network scheduler that allows traffic to share bandwidth equally, after being grouped by classes. The classes can be based upon a variety of parameters, such as priority, interface, or originating program. CBQ is a traffic management algorithm developed by the Network Research Group at Lawrence Berkeley National Laboratory as an alternative to traditional router-based technology. Now in the public domain as an open technology, CBQ is deployed by companies at the boundary of their WANs. CBQ divides user traffic into a hierarchy of classes based on any combination of IP addresses, protocols and application types. A company's accounting department, for example, may not need the same Internet access privileges as the engineering department. Because every company is organized differently and has different policies and business requirements, it is vital for traffic management technology to provide flexibility and granularity in cla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptive Virtual Queue
Adaptation, in biology, is the process or trait by which organisms or population better match their environment Adaptation may also refer to: Arts * Adaptation (arts), a transfer of a work of art from one medium to another ** Film adaptation, a story from another work, adapted into a film ** Literary adaptation, a story from a literary source, adapted into another work ** ** Theatrical adaptation, a story from another work, adapted into a play * ''Adaptation'' (film), a 2002 film by Spike Jonze * "Adaptation" (''The Walking Dead''), a television episode *''Adaptation'', a 2012 novel by Malinda Lo Biology and medicine * Adaptation (eye), the eye's adjustment to light ** Chromatic adaptation, visual systems' adjustments to changes in illumination for preservation of colors ** Prism adaptation, sensory-motor adjustments after the visual field has been artificially shifted * Cellular adaptation, changes by cells/tissues in response to changed microenvironments * High-altit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Latency
Network delay is a design and performance characteristic of a telecommunications network. It specifies the Latency (engineering), latency for a bit of data to travel across the network from one communication endpoint to another. It is typically measured in multiples or fractions of a second. Delay may differ slightly, depending on the location of the specific pair of communicating endpoints. Engineers usually report both the maximum and average delay, and they divide the delay into several parts: * Processing delay time it takes a router to process the packet header * Queuing delay time the packet spends in routing queues * Transmission delay time it takes to push the packet's bits onto the link * Propagation delay time for a signal to propagate through the media A certain minimum level of delay is experienced by signals due to the time it takes to Data transmission, transmit a packet serially through a Data link, link. This delay is extended by more variable levels of delay due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
