Quantifying the benefit of wavelength add-drop in WDM rings with distance-independent and dependent traffic

One drawback to deploying wavelength division multiplexed (WDM) synchronous optical network (SONET) rings is the potentially large amount of equipment necessary for their deployment, Wavelength add-drop multiplexers potential ly reduce the amount of required SONET terminal equipment by allowing indiv idual wavelengths to optically bypass a node rather than being electronical ly terminated. We have quantified the maximum terminal-equipment savings at tainable using wavelength add-drop for rings carrying uniform traffic and r ings carrying distance-dependent traffic. The analysis makes use of both an enumerative methodology, and a "super-node" approximation technique that i s applicable to arbitrary ring size and internode demand. In both the unifo rm and distance-dependent traffic scenarios, maximum terminal-equipment sav ings are shown to rapidly increase, ol er the region of interest, with both network size and internode demand. The value of wavelength add-drop is acc ordingly expected to grow rapidly in rings interconnecting numerous high-ca pacity nodes.