Patent ID: 6934472
Filing Date: 2005-08-23
Classification: H04J,H04Q

Abstract:
1. A system for multicasting a data payload through an optical network composed of a plurality of nodes interconnected by links wherein a given one of the nodes multicasts over two outgoing links, the data payload having a given format and protocol, the system comprising: a label-switch controller on said optical network; a route generator coupled to said label-switch controller and configured for generating and storing a local routing look-up table in each of the nodes, each local look-up table listing local addresses for determining alternative local routes through each of the nodes; an adder coupled to said label-switch controller and configured for adding a header to the data payload and embedded in the same wavelength as the data payload prior to inputting the data payload at an input one of the nodes to produce an optical signal, the header having a format and protocol and conveying multicast information indicative of local routes through the given node for the data payload and the header, the format and protocol of the data payload being independent of the format and protocol of the header; a switching device on said optical network which is configured for being controlled by the label-switching controller; a detector coupled to said switching device and configured for detecting the multicast information at the given one of the nodes to determine two switch control signals with reference to the multicast information as the data payload and the header propagate through the optical network; an optical splitter configured for splitting the optical signal received by said switching device into two split optical signals; a selector coupled to said switching device and configured for selecting two local routes through the given one of the nodes in correspondence to the two switch control signals; an optical switch having input ports and output ports wherein one of the split optical signals couples to a first input port and the second of the split optical signals couples to a second input port, and wherein one of the outgoing links couples to a first output port and the second of the outgoing links couples to a second output port; and a switch controller, coupled to the optical switch and responsive to the two switch control signals, configured for switching the optical switch in response to the multicast information to optically couple the first input port with the first output port and the second input port with the second output port; wherein the header is composed of one or more header signals each being conveyed by a distinct sub-carrier frequency and arranged so that the highest detectable sub-carrier frequency corresponds to an active header signal, the plurality of sub-carrier frequencies occupying a frequency band above the baseband spectrum of the data payload; a measurement device within said detector configured for concurrently measuring the header signals to produce a header selection signal; a second selector, coupled to the measurement device, configured for determining the active header signal as conveyed by the highest detectable sub-carrier frequency under control of the header selection signal to produce the switch control signals; a processor, responsive to the incoming optical signal within said detector and configured for detecting the multicast information and for deleting the header signals and recovering only the data payload; a header generator, responsive to the selector, and configured for determining a new active header signal conveying the multicast information; and means, responsive to the header generator, for inserting into the optical signal the new active header signal in place of the deleted header signals.