Optical Networking With Wavelength-Routing Feature Of Optical Crossconnects, Based On Wavelength-Division Multiplexing (Wdm) Technology, Is Now Regarded As The Emerging Solution For Next-Generation Long-Haul Telecommunication Backbones. Designing Such A Network, Referred To As Wavelength-Routed Optical Network (Wron), Is Constrained By Limited Network Resources And Transmission Impairments, And Can Be Formulated In General As An Optimization Problem. However, The Design Optimization For Wrons Turns Out To Be Np-Hard For Practical Networks, Eventually Leading To The Solutions Based On Heuristic Schemes. Thus, The Design Of Wrons Is, In Practice, Divided Into Component Subproblems. The _Rst Subproblem, Usually Referred To As Lightpath Topology Design (Ltd), Consists Of Provisioning End-To-End Optical Connections Or Lightpaths Between A Selected Set Of Nodes With Appropriate Routing And Wavelength Assignments (Rwa) Of The Lightpaths Over The Given Physical Topology. The Next Subproblem Deals With Distributing The Tra_C Streams Of All The Node Pairs Through The Limited Number Of Lightpaths Provisioned In The _Rst Subproblem. In View Of The Above, _Rst We Examined Some Ltd Methodologies Suitable For Initial Resource Provisioning For A Wron, Addressing The Constraints Of Limited Transmission Re- Sources, Along With An Improvised Awareness Of Tra_C Distribution Between Various Node Pairs. Subsequently, We Extended The Scope Of These Investigations Towards Addressing A Wdm-Speci_C Transmission Impairment, Viz., Impact Of Fwm Interference On Lightpath Performance, And Accommodate This Awareness In The Already-Examined Ltd Schemes Leading To An Fwm-Aware Ltd Methodology. In Particular, We Explored A Novel Wave- Length Assignment Scheme, Wherein An Equally-Spaced Channel Allocation Technique Is Employed For Restricting The _Ber Transmission Window, While Maintaining Fwm Gener- Ation Below An Acceptable Level. In Order To Keep The Fwm-Aware Ltd Scheme Simple For Implementation, The Impact Of Fwm Was Assessed Using A Count-Based Fwm Estimate. In Order To Verify The Usefulness Of The Simple Count-Based Measure, We Also Formulated An Analytical Model To Estimate The Actual Fwm Power At The End Of Each Lightpath In