In June 2004, the IEEE approved a new standard called Resilient Packet Ring (RPR), that is maintained in the 802 LAN/MAN Committee and designated standard number IEEE 802.17-2004. Among the features provided by the RPR technology are built-in QoS capabilities for traffic class differentiation, bidirectional transfer of data with destination stripping and spatial reuse and fast protection against node and link failure(s). In this paper, we introduce a framework used to specify the throughput of RPR, and propose a simple mapping between RPR's service classes and DiffServ Per Hop Behavior groups. We evaluate this mapping analytically, using a simple generic example, and by simulation using some selected scenarios. All our findings support that our proposed mapping between RPR's traffic classes and the PHB groups is indeed a viable one.