BufferbloatBufferbloat is a cause of high latency and jitter in packet-switched networks caused by excess buffering of packets. Bufferbloat can also cause packet delay variation (also known as jitter), as well as reduce the overall network throughput. When a router or switch is configured to use excessively large buffers, even very high-speed networks can become practically unusable for many interactive applications like voice over IP (VoIP), audio streaming, online gaming, and even ordinary web browsing.
GoodputIn computer networks, goodput (a portmanteau of good and throughput) is the application-level throughput of a communication; i.e. the number of useful information bits delivered by the network to a certain destination per unit of time. The amount of data considered excludes protocol overhead bits as well as retransmitted data packets. This is related to the amount of time from the first bit of the first packet sent (or delivered) until the last bit of the last packet is delivered.
Retransmission (data networks)Retransmission, essentially identical with automatic repeat request (ARQ), is the resending of packets which have been either damaged or lost. Retransmission is one of the basic mechanisms used by protocols operating over a packet switched computer network to provide reliable communication (such as that provided by a reliable byte stream, for example TCP). Such networks are usually "unreliable", meaning they offer no guarantees that they will not delay, damage, or lose packets, or deliver them out of order.
Sliding window protocolA sliding window protocol is a feature of packet-based data transmission protocols. Sliding window protocols are used where reliable in-order delivery of packets is required, such as in the data link layer (OSI layer 2) as well as in the Transmission Control Protocol (TCP). They are also used to improve efficiency when the channel may include high latency. Packet-based systems are based on the idea of sending a batch of data, the packet, along with additional data that allows the receiver to ensure it was received correctly, perhaps a checksum.
Fair queuingFair 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.
AQM (active queue management)In routers and switches, active queue management (AQM) is the policy of dropping packets inside a buffer associated with a network interface controller (NIC) before that buffer becomes full, often with the goal of reducing network congestion or improving end-to-end latency. This task is performed by the network scheduler, which for this purpose uses various algorithms such as random early detection (RED), Explicit Congestion Notification (ECN), or controlled delay (CoDel). RFC 7567 recommends active queue management as a best practice.
Binary exponential backoffExponential backoff is an algorithm that uses feedback to multiplicatively decrease the rate of some process, in order to gradually find an acceptable rate. These algorithms find usage in a wide range of systems and processes, with radio networks and computer networks being particularly notable. An exponential backoff algorithm is a form of closed-loop control system that reduces the rate of a controlled process in response to adverse events.
Contrôle de fluxLe contrôle de flux, dans un réseau informatique ou un réseau de télécommunications, représente un asservissement du débit binaire de l'émetteur vers le récepteur. Quand une machine a un débit montant supérieur au débit descendant de la destination, la source diminue son débit pour ne pas submerger le puits de requêtes (obligeant parfois, lorsque le puits ne peut pas les traiter, à la ré-émission de ces dernières). Le contrôle de flux doit être différencié du contrôle de congestion, qui est utilisé pour contrôler le flux de données lorsque la congestion a déjà eu lieu.
Service réseauDans le cas d'un réseau informatique, un service réseau est une application exécutée depuis la couche d'application réseau et au-dessus. Il fournit des capacités de stockage, de manipulation, de présentation, de communication ou d'autres services qui sont souvent mises en œuvre en utilisant une architecture client-serveur ou pair à pair basée sur un protocole de communication de la couche « application » du modèle OSI.
