The IEEE 802.17 specifications for a medium access control (MAC) layer protocol that uses Ethernet switching and a dual counter-rotating ring topology to optimize the transport of Ethernet/IP packet data traffic over optical fiber rings. RPR is designed to maintain the resiliency of SONET/SDH, but at a much reduced level of overhead.As RPR is independent of the Physical Layer, it can be implemented over existing SONET/SDH physical rings or can run on a standalone basis. RPR calls for dual counter-rotating local ringlets that interconnect nodes where data traffic is intended to drop. RPR also uses statistical multiplexing, which allows bandwidth to be oversubscribed, while establishing Committed Information Rate (CIR) and peak-rate thresholds per application. The nodes negotiate bandwidth requirements among themselves based on fairness algorithms and in consideration of a classification scheme that recognizes and provides higher priority access to traffic sensitive to latency and jitter while ensuring that best effort traffic, such as Internet traffic, is afforded equal access and a fair share of the remaining bandwidth. RPR supports the following class of service (CoS) levels: