A communications system has a plurality of islands, and a media path having resources for carrying data in a plurality of calls between first and second ones of the islands. Each of the first and second islands has a controller for managing allocation of the resources of the media path between the plurality of calls. A faulty controller is detected, and either replaced with a working replacement controller or recovered to working order. A further controller provides to the replacement or recovered controller, on replacement or recovery, information on the allocation of the resources of the media path.