A mechanism of dynamic meter sharing on openflow switch

Per-flow rate-limiting is one of quality of the service (QoS) challenge in networking system. It is difficult to find a method that is both quick and efficient to manage flows which need to be limited to different rates due to the limitation of hardware resources. However, in OpenFlow-1.3 specification, the Meter part describes the definition of per-flow rate limiting. According to the description of Meter, this paper provides a detailed implementation of Meter based on ONetSwitch hardware platform and verifies the performance through multiple groups of experiment. Through the statistic of flows in network, there are only 100 active flows in million network in-progress flows. Therefore, the per-flow rate limiting problem may be resolved through multiple flows time sharing hardware resources. Referencing the idea of Dynamic Queue Sharing (DQS), Dynamic Meter Sharing (DMS) was proposed in this paper to schedule among different flows that sharing the same rate limiting pipe, but during different period. However, the number of rate limiters is limited due to the limitation of hardware resources. When flow numbers exceed the number of rate limiters, it is unavoidable to allocate some flows to a shared rate limiter waiting for idle ones. Although the critical "per-flow rate limiting" is not achieved, Meter has an advantage over traditional rate limiting method. The results show that Meter allocate an independent rate limiter for per-flow, then realize limiting multiple flows in different rate.