In a configuration wherein N individual fibers interconnect two devices, each fiber can be configured, through configuration of the packet processing devices at each end of the fiber, to carry traffic in a single direction. From the perspective of the first device, an arbitrary subset T of the N fibers can be used for transmitting signals to the second device. The packet processing devices terminating a subset R of the remaining N-T fibers can be configured so that the first device may receive signals from the second device.