Fibre Channel SAN Extension over IP IP Transport Architectures
IP Transport Architectures
Campus/Metro Ethernet
Short distance <= 60km
SONET/SDH
SONET/SDH
Medium distance <= 160km
IP Routed WAN
Long distance > 160km
Routed IP WAN:
Frame Relay ATM
Packet-over-SONET (POS)
Ethernet:
Campus (owned) Metro GigE (leased)
A number of options are available for transporting FCIP. In general, the choice will depend primarily on the desired distance, although cost, bandwidth, and latency are obviously factors as well: Campus Ethernet is the obvious choice if a local Ethernet infrastructure is feasible, and many service providers are now offering Metro Gigabit Ethernet service in major metropolitan areas. A campus or metro Gigabit Ethernet or short-haul, high-bandwidth SONET/SDH implementation is suitable for some synchronous applications because it can provide the high bandwidth and low latency required by synchronous replication schemes.
SONET/SDH can provide the same (or even greater) bandwidth as a campus or leased metro Ethernet infrastructure, over longer distances, but at a higher cost. A long-haul SONET/SDH implementation provides moderate latency, which may be a problem for latency-sensitive applications like synchronous mirroring. This type of implementation would be good for asynchronous mirroring or remote backup.