Ever-increasing traffic in the long-haul networks called for WDM-based transmission, all the more when compared to the metro and access segments. Further, although the interconnected WDM rings served the needs of long-haul networks for some time, mesh-connected WDM networks appeared as a natural and more effective solution, with enhanced connectivity and resilience against network failures. In this chapter, we first examine the basic design challenges and the candidate node configurations for WRON-based mesh networks. Next we present various offline design methodologies for this class of networks using LP-based and heuristic schemes. Impact of wavelength conversion (WC) in mesh-configured WRONs is also examined by using analytical models, and the gain in bandwidth utilization is assessed in WRONs with full WC as compared to those without any WC. Finally, we examine some online routing and wavelength assignment schemes that can be used for operational WRONs. (143 words)