an optical signaling header technique applicable to optical networks wherein packet routing information is embedded in the same channel or wavelength as the data payload so that both the single - sideband modulated header and data payload propagate through network elements with the same path and the associated delays . the header routing information has sufficiently different characteristics from the data payload so that the signaling header can be detected without being affected by the data payload , and that the signaling header can also be removed without affecting the data payload . the signal routing technique can be overlaid onto the conventional network elements in a modular manner using two types of applique modules . the first type effects header encoding and decoding at the entry and exit points of the data payload into and out of the network ; the second type effects header detection at each of ~ the network elements .