An apparatus includes a data flow circuit and a clock recovery circuit. The data flow circuit is configured to extract client data, which is encapsulated in an inner frame that is encapsulated in at least an outer frame, and to output the extracted client data in accordance with a client clock signal. The clock recovery circuit includes a first clock recovery module that is configured to recover a first clock signal that matches payload data in the outer frame, and a second clock recovery module that is configured to derive from the first clock signal a second clock signal that matches the client data in the inner frame, and to produce the client clock signal from the second clock signal, for use by the data flow circuit.