Fibre Channel SAN Extension over Optical Networks WAN Design Metrics
WAN Design Metrics
DWDM SONET CWDM Cost Metro Ethernet Public IP
Distance
Large enterprises are more likely have the resources to implement optical solutions like CWDM, DWDM, and SONET/SDH, and may already have dark fibre in place. Distance –
Metro Ethernet is 60km CWDM – 120km DWDM – 250km SONET – can go a lot further (dependent on the number of regenerators you implement) because it can be regenerated.
IP –
would give us the longest distance (global) and the lowest cost but at the cost of latency.
For synchronous replication the maximum recommended distance is 125km over optical extension, i.e. CWDM or DWDM. If DWDM connections were 250km the recommendation would be to use asynchronous replication because of the added latency going over the fibre.