Fairness with N Rate N+1 Color Marking on Cascade Aggregation for Access Network
Yu Nakayama, 憲行 太田 · 2011
With cascade aggregation, which can enable access networks to be deployed efficiently in areas with a low subscriber density, the problem arises of unfairness of Best Effort (BE) traffic between subscribers. This paper proposes an N rate N+1 color marking (NRN+1CM) function for achieving bandwidth fairness on cascade aggregation. The basic idea behind NRN+1CM is to color subscribers' BE frames and discard BE frames based on queue length and frame color. Multicolor markers have been studied but existing multicolor markers cannot estimate burst traffic rates accurately. We propose a multicolor marker with a single token bucket. The proposed marker can select a color from N+1 colors according to the traffic rate, independent of burstiness. NRN+1CM is scalable because it works on a simple queue configuration without messaging between layer-2 switches. Numerical simulations show that NRN+1CM can select colors accurately and achieve approximately fair bandwidth sharing.