ABSTRACT
Constraint (18.8) indicates the wavelength continuity constraint for primary lightpaths. Constraint (18.9) ensures that primary lighpaths do not share a wavelength with any backup lightpaths on the same fiber link. Constraint (18.10) indicates the wavelength continuity constraint for backup lightpaths where the corresponding primary lightpaths belong to the same SRLG. Constraint (18.11) ensures the existence of the backup lightpath on the same wavelength that the primary lightpath is using; therefore, the wavelength continuity constraint can still be guaranteed after a failure occurs.
