On a Cisco switch, ports are always a member of a VSAN.
VSAN membership is assigned on a port-by-port basis. Up to 256 VSANs can be configured on a physical SAN. VSANs are identified by the VSAN ID, which can be one of the following:
• VSAN 1 is the default VSAN. • VSAN 4094 is an isolated VSAN. • User-defined VSAN IDs range from 2 to 4093.
The default VSAN has the following characteristics:
• It is the VSAN to which ports are assigned until they are assigned to another VSAN.
• If no VSANs are configured, all devices in the fabric are considered part of the default VSAN.
• It is the only VSAN enabled by default for switches in the Cisco MDS 9000 Family.