[2] It is designed to provide the resilience found in SONET and Synchronous Digital Hierarchy networks (50 ms protection) but, instead of setting up circuit oriented connections, provides a packet based transmission, in order to increase the efficiency of Ethernet and IP services.
RPR uses Media Access Control protocol (MAC) messages to direct the traffic, which can use either ringlet of the ring.
Class A (or High) traffic is a pure committed information rate (CIR) and is designed to support applications requiring low latency and jitter, such as voice and video.
Class B (or Medium) traffic is a mix of both a CIR and an excess information rate (EIR; which is subject to fairness queuing).
One drawback of the first version of RPR was that it did not provide spatial reuse for frame transmission to/from MAC addresses not present in the ring topology.