The invention relates to a method in a border node of an optical network and in an external optical channel originating apparatus and to a border node of an optical network and a router. The invention is particularly applicable to optical path validation in an optical network for an externally originating optical channel. The invention may be used during an optical path fault recovery operation.In the method in a border node of an optical network optical channel traffic parameter associated with an optical channel are received from an optical channel originator external to the optical network. The received optical channel traffic parameters are used to determine the suitability of at least one optical path within the optical network for an externally originating optical channel. If a suitable optical path is determined an optical channel availability message indicating the availability at the border node of an optical path within the optical network for the optical channel is sent to the optical channel originator.In the method in an optical channel originator external to an optical network the optical channel traffic parameters associated with an optical channel originating at the optical channel originator are sent to a border node of the optical network. An optical channel availability message indicating the availability at the optical network border node of an optical path within the optical network for the optical channel with which the optical channel traffic parameters are associated is received from the border node. An available optical channel status of the optical channel is determined from the received optical channel availability message for the optical channel.