N Rate ${\rm N}+1$ Color Marking: Per-Flow Fairness in Ring Aggregation Networks

Our study is motivated by the need for per-flow fairness in a ring aggregation network. This paper proposes a multicolor marking and queuing delay suppression scheme called N rate N + 1 color marking (NRN + 1 CM) that is designed to achieve per-flow fairness. The key idea is to assign a color to a frame according to the flow input rate with high burst tolerance using a simple marker. The color indicates the dropping priority. When congestion occurs, frames are selectively discarded based on their color and the dropping threshold. The accumulation of queuing delay is suppressed with a dropping threshold notification process. The effect of NRN+1 CM was confirmed by a theoretical analysis and computer simulations.