Resilient Packet Ring (RPR), also known as IEEE 802.17, is a protocol standard designed for the optimized transport of data traffic over optical fiber ring networks. The standard began development in November 2000 and has undergone several amendments since its initial standard was completed in June 2004. The amended standards are 802.17a through 802.17d, the last of which was adopted in May 2011. It is designed to provide the resilience found in SONET/SDH 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.