Patent ID: 6271946
Filing Date: 2001-08-07
Classification: H04J,H04Q

Abstract:
A method for propagating an input data payload from an input network element to an output network element in a wavelength division multiplexing (WDM) network composed of a plurality of network elements each including a switch, the input data payload having a given format and protocol, the method comprising the steps ofgenerating and storing a local routing look-up table in each of the network elements, each local routing table determining alternative local routes through the associated one of the network elements,generating and storing replicated versions of the input data payload in the input network element,adding an optical header to each of the replicated versions of the input data payload to produce a plurality of corresponding optical signals, the header having a format and protocol and being indicative of the local route through each of the network elements for each of the optical signals, the format and protocol of the data payload being independent of the format and protocol of the header,optically transmitting each of the optical signals over a corresponding one of the links,detecting the header of each of the optical signals at the network elements to produce a corresponding switch control signal as each of the optical signals propagates through the WDM network,selecting one of the local routes for routing each of the optical signals through each of the network elements by looking up the switch control signal in the corresponding local routing table to operate the corresponding switch, androuting each of the optical signals to the output network element through the network elements in correspondence to the selected route,wherein each 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 input data payload, the step of detecting including the steps ofconcurrently measuring the header signals to produce a header selection signal,selecting the active header signal as conveyed by the highest detectable sub-carrier frequency under control of the header selection signal, andprocessing the active header signal to obtain the switch control signal for routing the optical signal.