Access delay performance of resilient packet ring under bursty periodic class B traffic load

The IEEE P802.17 workgroup is currently standardizing a ring network architecture and associated protocol called Resilient Packet Ring (RPR). In addition to high-priority guaranteed class A traffic and best-effort class C traffic, RPR supports low-jitter, delay bounded, medium priority class B traffic. This class can, for example, be allocated for VBR streaming video or interactive on-line games. These traffic types are notorious for their bursty periodic profiles. This paper reports on simulation results of several scenarios using the conservative fairness algorithm under varying bursty periodic class B traffic loads competing with background class C traffic. For both one- and two-transit buffer stations, we found that in order to minimize the access and end-to-end delay of class B traffic, the shaperB committed access rate parameter should be configured as the sum of the class BCIR and BEIR provisioned bandwidth instead of BCIR only. Our simulations show that as the periodic bursts magnitude increases, the class B access delay increases in function of fairness round-trip time, rate thresholds and number of stations adding class B traffic.