SAN components
There are three main components in a Storage Area Network, which are Interface, Interconnect and Fabric.
Interface
The Interface allows storage to be external from the server and allows server clustering. The common SAN Interfaces are SCSI, Fibre Channel and other protocols.
Interconnect
The Interconnect is the mechanism that multiple devices exchange data. Devices such as multiplexers, hubs, routers, gateways and switchers are used to link various Interfaces to Fabrics.
Fabric
The Fabric is the platform based on switched SCSI, switched Fibre Channel or etc. The platform is the combination of network protocol and network topology. The use of gateways allows the SAN to be extended across WANs.
Fibre Channel
Fibre Channel has been used as an alternative to SCSI in generating high-speed links among network devices. This type of Interface was developed by ANSI in the early 1990s, purposely as a means to transfer large amounts of data at faster rates. Fibre Channel is compatible with SCSI, IP, IEEE, 802.2, ATM Adaptation Layer for computer data, and Link Encapsulation, and it can be used over copper cabling or fiber-optic cable. Fibre Channel supports data rates of 133 Megabytes per second (Mbps), 266 Mbps, 532 Mbps and 1.0625 Gigabytes per second. In the near future, most probably there will be data rates of 4 Gigabytes per second. Currently, this technology supports distances of up to 10 kilometers, which indeed is a good choice for disaster recovery.
It is known that installing a Storage Area Network does not essentially mean organizations will have to change all their storage hardware. SCSI-to-Fibre Channel converters allow most accessible storage subsystems to be included into a SAN.