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Differentiated Services
Differentiated services or DiffServ is a computer networking architecture that specifies a mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks. DiffServ can, for example, be used to provide low-latency to critical network traffic such as voice or streaming media while providing best-effort service to non-critical services such as web traffic or file transfers. DiffServ uses a 6-bit differentiated services code point (DSCP) in the 6-bit differentiated services field (DS field) in the IP header for packet classification purposes. The DS field, together with the ECN field, replaces the outdated IPv4 TOS field. Background Modern data networks carry many different types of services, including voice, video, streaming music, web pages and email. Many of the proposed QoS mechanisms that allowed these services to co-exist were both complex and failed to scale to meet the demands of the public Internet. In December 1998, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Networking
A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or by wireless communication. The devices may be connected in a variety of network topologies. In order to communicate over the network, computers use agreed-on rules, called communication protocols, over whatever medium is used. The computer network can include personal computers, Server (computing), servers, networking hardware, or other specialized or general-purpose Host (network), hosts. They are identified by network addresses and may have hostnames. Hostnames serve as memorable labels for the nodes and are rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol. Computer networks may be classified by many criteria, including the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Router (computing)
A router is a computer and networking device that Packet forwarding, forwards data packets between computer networks, including internetworks such as the global Internet. Routers perform the "traffic directing" functions on the Internet. A router is connected to two or more data lines from different IP networks. When a data packet comes in on a line, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Data packets are forwarded from one router to another through an internetwork until it reaches its destination Node (networking), node. The most familiar type of Internet Protocol, IP routers are Residential gateway, home and small office routers that forward IP packet (other), IP packets between the home computers and the Internet. More sophisticated routers, such as enterprise routers, conne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 equal subparts, WFQ allows schedulers to specify, for each flow, which fraction of the capacity will be given. Weighted fair queuing is also known as packet-by-packet GPS (PGPS or P-GPS) since it approximates generalized processor sharing "to within one packet transmission time, regardless of the arrival patterns." Parametrization and fairness Like other GPS-like scheduling algorithms, the choice of the weights is left to the network administrator. There is no unique definition of what is "fair" (see for further discussion). By regulating the WFQ weights dynamically, WFQ can be utilized for controlling the quality of service Quality of service (QoS) is the description or measurement of the overall performance of a service, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fair Queuing
Fair queuing is a family of scheduling algorithms used in some process and network schedulers. The algorithm is designed to achieve fairness when a limited resource is shared, for example to prevent flows with large packets or processes that generate small jobs from consuming more throughput or CPU time than other flows or processes. Fair queuing is implemented in some advanced network switches and routers. History The term ''fair queuing'' was coined by John Nagle in 1985 while proposing round-robin scheduling in the gateway between a local area network and the internet to reduce network disruption from badly-behaving hosts. A byte-weighted version was proposed by Alan Demers, Srinivasan Keshav and Scott Shenker in 1989, and was based on the earlier Nagle fair queuing algorithm. The byte-weighted fair queuing algorithm aims to mimic a bit-per-bit multiplexing by computing theoretical departure date for each packet. The concept has been further developed into weighted fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Admission Control
Admission control is a validation process in communication systems where a check is performed before a connection is established to see if current resources are sufficient for the proposed connection. Applications For some applications, dedicated resources (such as a wavelength across an optical network) may be needed in which case admission control has to verify availability of such resources before a request can be admitted. For more elastic applications, a total volume of resources may be needed prior to some deadline in order to satisfy a new request, in which case admission control needs to verify availability of resources at the time and perform scheduling to guarantee satisfaction of an admitted request. Admission control systems *Asynchronous Transfer Mode * Audio Video Bridging using Stream Reservation Protocol * Call admission control *IEEE 1394 * Integrated services on IP networks *Public switched telephone network The public switched telephone network (PSTN) is the a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strict Priority Queuing
In computer science, a priority queue is an abstract data type similar to a regular queue or stack abstract data type. In a priority queue, each element has an associated ''priority'', which determines its order of service. Priority queue serves highest priority items first. Priority values have to be instances of an ordered data type, and higher priority can be given either to the lesser or to the greater values with respect to the given order relation. For example, in Java standard library, ''PriorityQueues the least elements with respect to the order have the highest priority. This implementation detail is without much practical significance, since passing to the opposite order relation turns the least values into the greatest, and vice versa. While priority queues are often implemented using heaps, they are conceptually distinct. A priority queue can be implemented with a heap or with other methods; just as a list can be implemented with a linked list or with an array. Op ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explicit Congestion Notification
Explicit Congestion Notification (ECN) is an extension to the Internet Protocol and to the Transmission Control Protocol and is defined in (2001). ECN allows end-to-end notification of network congestion without dropping packets. ECN is an optional feature that may be used between two ECN-enabled endpoints when the underlying network infrastructure also supports it. Conventionally, TCP/IP networks signal congestion by dropping packets. When ECN is successfully negotiated, an ECN-aware router may set a mark in the IP header instead of dropping a packet in order to signal impending congestion. The receiver of the packet echoes the congestion indication to the sender, which reduces its transmission rate as if it detected a dropped packet. Rather than responding properly or ignoring the bits, some outdated or faulty network equipment has historically dropped or mangled packets that have ECN bits set. , measurements suggested that the fraction of web servers on the public Internet ... [...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 traf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Policing (communications)
Traffic is the movement of vehicles and pedestrians along land routes. Traffic laws govern and regulate traffic, while rules of the road include traffic laws and Norm (sociology), informal rules that may have developed over time to facilitate the orderly and timely flow of traffic. Organized traffic generally has well-established priorities, lanes, right-of-way, and traffic control at intersection (road), intersections. (International Regulations for Preventing Collisions at Sea govern the oceans and influence some laws for navigating domestic waters.) Traffic is formally organized in many jurisdictions, with marked lanes, Junction (traffic), junctions, Intersection (road), intersections, interchange (road), interchanges, traffic signals, Traffic cone, cones, or traffic sign, signs. Traffic is often classified by type: heavy motor vehicle (e.g., car, truck), other vehicle (e.g., moped, bicycle), and pedestrian. Different classes may share speed limits and easement, or may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rate Limiting
In computer networks, rate limiting is used to control the rate of requests sent or received by a network interface controller. It can be used to prevent DoS attacks and limit web scraping. Research indicates flooding rates for one zombie machine are in excess of 20 HTTP GET requests per second, legitimate rates much less. Rate limiting should be used along with throttling pattern to minimize the number of throttling errors. Hardware appliances Hardware appliances can limit the rate of requests on layer 4 or 5 of the OSI model. Rate limiting can be induced by the network protocol stack of the sender due to a received ECN-marked packet and also by the network scheduler of any router along the way. While a hardware appliance can limit the rate for a given range of IP-addresses on layer 4, it risks blocking a network with many users which are masked by NAT with a single IP address of an ISP. Deep packet inspection can be used to filter on the session layer but will eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huawei
Huawei Technologies Co., Ltd. ("Huawei" sometimes stylized as "HUAWEI"; ; zh, c=华为, p= ) is a Chinese multinational corporationtechnology company in Longgang, Shenzhen, Longgang, Shenzhen, Guangdong. Its main product lines include telecommunications equipment, consumer electronics, electric vehicle self-driving car, autonomous driving systems, and rooftop solar power products. The company was founded in Shenzhen in 1987 by Ren Zhengfei, a veteran officer of the People's Liberation Army (PLA). Initially focused on manufacturing stored program control, phone switches, Huawei has expanded to more than 170 countries to include building telecommunications network infrastructures, providing equipment, operational and consulting services, and manufacturing communications devices for the consumer market. It overtook Ericsson in 2012 as the largest telecommunications equipment manufacturer in the world. Huawei surpassed Apple Inc., Apple and Samsung Electronics, Samsung, in 2018 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
