This ITU-T specification is directly based on and derived from the Ethernet Automatic Protection Switching technology developed and patented by Extreme Networks.
ERPS specifies protection switching mechanisms and a protocol for Ethernet layer network (ETH) rings.
Ethernet Rings can provide wide-area multipoint connectivity more economically due to their reduced number of links.
The mechanisms and protocol defined in this Recommendation achieve highly reliable and stable protection; and never form loops, which would fatally affect network operation and service availability.
(Note that a single link failure anywhere in the ring ensures a loop free topology.)