We are dealing with a CWDM system used for taking the information from one SAN location to other SAN location. ESCON, FICON and gigabit Ethernet from SAN devices can be hooked directly into our system. Is this system for disaster recovery outdated or is it still in?
Wave division multiplexing (WDM) based solutions including coarse WDM (CWDM) and dense WDM (DWDM) are still very applicable. WDM is a good solution for spanning distances and increasing network bandwidth when dedicated dark fiber optic cable is available. CWDM is great for applications and environments that do not need longer distances or lots of network bandwidth compared to DWDM. Some things to consider for your environments are doing it on your own or leasing the dedicated (dark) fiber optic cable between your locations. Do you need more bandwidth and lambdas (light wavelengths) to support more dedicated network interfaces? Do you need to support higher network interface speeds including 4 Gb Fibre Channel or 10 Gb Ethernet or 10 Gb Fibre Channel? Based on these questions, you may consider upgrading to DWDM if you need more bandwidth, wavelengths and if you own the fiber optic cable or if the recurring monthly costs for the dark fiber cable are reasonable. Some alternative solutions would include SONET/SDH using time division multiplexing (TDM) or IP-based services and gateways, routers, and channel extension devices.