IEEE 802.17, Resilient Packet Ring (RPR), is a new technology for ring-based metropolitan area networks that enables efficient transfer of data traffic as well as fast protection mechanisms. Many metropolitan networks use a physical ring structure. It is a natural environment for the SONET/SDH networks that con- stitute the bulk of current metropolitan network infrastructure. This article deals with the fundamentals and current standardization efforts for IEEE 802.17 Resilient Packet Ring (RPR). Its special resilience features make this technology robust against outages of the network infrastructure. The article overviews the fundamentals of RPR and the standardization process carried out under the auspices of IEEE and the International Telecommunication Union. Some potentially hazardous situations involving traffic assignments have also been defined and illustrated. A possible situations where the simplicity, enhanced throughput, and automatic resilience features of RPR may be advantageous for network operators have been identified in the concluding part.