Fibre Channel SAN Extension over Optical Networks WAN Design Metrics
Applications for SAN Extension
Synchronous replication
CWDM DWDM Metro Ethernet SONET Public IP
Asynchronous replication
Remote tape vaulting
Business continuance and disaster recovery applications are the most common applications for SAN extension: Synchronous replication requires high bandwidth and low latency, and CWDM and DWDM may provide the best solutions for these applications. For longer distances, FC-over-SONET can sometimes be used for synchronous replication. Asynchronous replication also requires high bandwidth but can tolerate more latency, so FC-over-SONET can provide a more cost-effective solution in addition to supporting longer distances than WDM solutions. Metro GigE can also be used here. Remote tape vaulting applications can tolerate higher latency, but still need deterministic (consistent) latency. For these solutions, FC-over- SONET or FCIP-over-POS can be a cost-effective solution. In addition SSPs that host remote vaulting solutions are currently more likely to provide SONET connectivity than WDM.