An optical cable is considered as a multicomponent system, which components are elementary sections of an optical cable. During operation, due to failures of these sections, they are replaced with new ones. The reason for the failures of elementary sections, which we will call local failures, are sudden failures. In addition to sudden failures, there are gradual failures that are a consequence of the fiber aging. There is a need to replace the optical cable as a whole. Such a failure is wear-out or global. The influence of sudden failures on the reliability measures of an optical cable in the conditions of its degradation is considered. To solve this problem, a Markov reliability model was developed, on the basis of which expressions were obtained for calculating the unavailability factor, the average time of operational and inoperable states during the degradation cycle of an optical cable. Methods for determining the probabilities of transitions from one state of degradation to another are proposed. It is shown that the unavailability factor of the optical cable and the average time of operational state on one degradation cycle increase with increasing intensity of sudden failures. The optical cable reliability model presented in this paper can be useful for predicting the operating time of an optical cable.