Weighted round robin

Weighted round robin, often shortened to WRR, is a network scheduler for data flows that is also used to schedule processes. It generalises ordinary round-robin scheduling. Round robin cycles over a set of queues or tasks and gives each one service opportunity per cycle, whereas weighted round robin gives each queue or task a fixed number of opportunities set by its configured weight, which influences the share of capacity that queue or task receives. On a computer network a service opportunity is the emission of one packet when the selected queue is not empty. When every packet has the same size, WRR is the simplest approximation of generalized processor sharing. Several variations exist, and the two main ones are the classical form, which serves a queue up to its weight in one visit, and the interleaved form, which splits each cycle into rounds.