In an optical fiber ring topology network such as FDDI (Fiber Distributed Data Interface) rings and SONET (Synchronous Optical Network) rings, the number of consecutively bypassed failed stations is limited by the optical power loss constraint. In recent years, this situation was represented as a consecutive k-out-of-n:F system and the two-terminal reliability was presented in the literature, but K-terminal reliability has not been presented. In this paper, we obtain K-terminal reliability expressions for dual-counter rotating networks (DR's) that use both self-heal and station-bypass switches in which all components (stations, links and bypass switches) can fail. The results are useful in evaluating the reliabilities of FDDI ring networks parametrically and making reliability comparisons. This method can be used to obtain a closed-form reliability expression in a more general ring-network such as 'ring of trees.'