Patent ID: 6819666
Filing Date: 2004-11-16
Classification: H04J,H04Q

Abstract:
A method for multicasting a data payload from an input network element to a plurality of output network elements in an optical network composed of a plurality of network elements, the data payload having a given format and protocol, the method comprising the steps ofgenerating and storing a local look-up table in each of the network elements, each local look-up table listing local addresses for determining alternative local routes through each of the network elements, adding a plurality of headers to the data payload and embedded in the same wavelength as the data payload prior to inputting the data payload to the input network element to produce an optical signal, each of the headers having a format and protocol and conveying multicast information indicative of a local route through each of the network elements for the data payload and the headers, the format and protocol of the data payload being independent of the format and protocol of the headers, detecting the multicast information at the network elements to determine a plurality of the local addresses with reference to the multicast information as the data payload and the headers propagate through the optical network, selecting a plurality of local routes, in correspondence to the plurality of the local addresses, for routing the optical signal through each of the network elements as determined by looking up the plurality of the local addresses in the corresponding local look-up table, and routing the optical signal through each of the network elements in correspondence to the selected routes, wherein the headers are conveyed by a single sideband signal occupying a given frequency band above the data payload, the step of detecting including the steps of opto-electrically converting the optical signal to detect the headers, and processing the headers to detect the multicast information, the method further comprising, prior to the step of routing, the steps of optically filtering the optical signal with a reflective part of a notch filter to delete the headers and recover the data payload, and inserting new single-sideband headers at the given frequency band into the optical signal in place of the deleted headers.