Optical layer multicasting using a single sub-carrier header with active header detection, deletion, and new header insertion via opto-electrical processing

A method in a multicast optical network for relpacing a header in an optical signal propagating at a given wavelength, the optical signal including the header and a data payload, the header being 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 data payload, the header containing multicast information as sub-headers in each of the header signals for routing the optical signal through a switch, the method comprising the steps of

• opto-electrically converting the optical signal to detect the header,
• reading the header to obtain the multicast information,
• optically processing the optical signal to delete the header, and
• inserting a new header into the optical signal in place of the deleted header to convey the multicast information.

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 of

• generating and storing a local look-up table in each of the network elements, each local routing table listing local addresses for determining alternative local routes through each of the network elements,
• adding a header 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, the header having a format and protocol and conveying multicast information indicative of local routes through each of the network elements 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,
• detecting the multicast information at the network elements to determine switch control signals with reference to the multicast information as the data payload and header propagate through the optical network, and
• switching an optical switch, in response to the switch control signals, to route the optical signal over a plurality of local routes through each of the network elements,
• wherein the header is composed of a header signal being conveyed by a distinct carrier frequency such that the spectrum of the header signal occupies a frequency band above the data payload,
• the step of detecting including the steps of
• opto-electrically converting the optical signal to detect the header signal, and
• reading the header signal to obtain the multicast information, the method further comprising, prior to the step of routing, the steps of
• optically processing the optical signal to delete the header signal and recover only the data payload, and
• inserting a new header signal into the optical signal in place of the deleted header signal to convey the multicast information.

A system for multicasting a data payload from an input network element to an output network element in an optical network composed of a plurality of network elements, the data payload having a given format and protocol, the system comprising

• a route generator for generating and storing a local routing 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,
• an adder for adding a header 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, the header having a format and protocol and conveying multicast information indicative of local routes through each of the network elements 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 detector for detecting the multicast information at the network elements to determine a plurality of local addresses with reference to the multicast information as the data payload and the header propagate through the optical network, and
• a selector for selecting a plurality of local routes, in correspondence to the plurality of 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,
• wherein the header is composed of a header signal being conveyed by a distinct carrier frequency such that the spectrum of the header signal occupies a frequency band above the data payload,
• the detector further comprising
• an opto-electrical converter for opto-electrically converting the optical signal to detect the header signal, and
• a reader for reading the header signal to obtain the multicast information,
• the system further comprising
• an optical processor, responsive to the optical signal, for processing the optical signal to delete the header signal and recover only the data payload, and
• means, responsive to the optical processor, for inserting a new header signal into the optical signal in place of the deleted header signal to convey the multicast information.

A system for multicasting a data payload from an input network element to an output network element in an optical network composed of a plurality of network elements, the data payload having a given format and protocol, the system comprising

• a route generator for generating and storing a local routing 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,
• an adder for adding a header 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, the header having a format and protocol and conveying multicast information indicative of local routes through each of the network elements 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 detector for detecting the multicast information at the network elements to determine switch control signals with reference to the multicast information as the data payload and the header propagate through the optical network,
• a selector for selecting a plurality of local routes, in correspondence to the number of switch control signals, and
• an optical switch, responsive to the switch control signals, for routing the optical signal over the plurality of local routes through each of the network elements,
• wherein the header is composed of a header signal being conveyed by a distinct carrier frequency such that the spectrum of the header signal occupies a frequency band above the data payload,
• the detector further comprising
• an opto-electrical converter for opto-electrically converting the optical signal to detect the header signal, and
• a reader for reading the header signal to obtain the multicast information,
• the system further comprising
• an optical processor, responsive to the optical signal, for processing the optical signal to delete the header signal and recover only the data payload, and
• means, responsive to the optical processor, for inserting a new header signal into the optical signal in place of the deleted header signal to convey the multicast information.