Patent ID: 7634167

Claim:
A method of determining the feasibility of a composite optical path in an optical communications network, the composite optical path being composed of at least two optical paths k 1 and k 2 , the method comprising: for each individual optical path k having a type i interface in a composite optical path, defining at least one parameter indicating a feasibility of the individual optical path k; calculating a quality Q factor Q′_i,k 1 +k 2 of an estimated signal to be transmitted over the composite optical path based on one or more factors that cause deterioration of the signal over the individual optical paths k 1 and k 2 ; comparing the quality Q factor with a value Qbare_i, where Qbare_i is defined as the lowest acceptable input value into a mapping function Q_i(.) that, for a given interface i, is configured to output the quality Q factor as a function of an Optical Signal to Noise Ratio (OSNR) received and evaluated under worst case conditions while ensuring the desired signal quality; and verifying that the composite optical path is feasible if Q′_i,k 1 +k 2 >=Qbare_i.