Virtual SAN (VSAN) technology partitions a single physical SAN into multiple VSANs. VSAN capabilities allow Cisco NX-OS software to logically divide a large physical fabric into separate, isolated environments to improve Fibre Channel SAN scalability, availability, manageability, and network security. For FICON, VSANs facilitate hardware-based separation of FICON and open systems.
Each VSAN is a logically and functionally separate SAN with its own set of Fibre Channel fabric services. This partitioning of fabric services greatly reduces network instability by containing fabric reconfigurations and error conditions within an individual VSAN. The strict traffic segregation provided by VSANs helps ensure that the control and data traffic of a specified VSAN are confined within the VSAN’s own domain, increasing SAN security. VSANs help reduce costs by facilitating consolidation of isolated SAN islands into a common infrastructure without compromising availability.
Users can create administrator roles that are limited in scope to certain VSANs. For example, a network administrator role can be set up to allow configuration of all platform-specific capabilities, while other roles can be set up to allow configuration and management only within specific VSANs. This approach improves the manageability of large SANs and reduces disruptions due to human error by isolating the effect of a user action to a specific VSAN whose membership can be assigned based on switch ports or the worldwide name (WWN) of attached devices.
VSANs are supported across FCIP links between SANs, which extends VSANs to include devices at a remote location. The Cisco MDS 9000 Family switches also implement trunking for VSANs. Trunking allows Inter-Switch Links (ISLs) to carry traffic for multiple VSANs on the same physical link.