The interconnection of choice in today's SAN is Fibre Channel, which has been used as an alternative to SCSI in creating high-speed links among network devices.

Fibre Channel was developed by ANSI in the early 1990s, specifically as a means to transfer large amounts of data very fast. 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.

Currently, Fibre Channel supports data rates of 133Mbytes/sec, 266Mbytes/sec, 532Mbytes/sec, and 1.0625Gbits/sec. A proposal to bump speeds to 4Gbits/sec is on the drawing board. The technology supports distances of up to 10 kilometers.

There are three major Fibre Channel topologies,

• Point-to-Point (FC-P2P). Two devices are connected back to back. This is the simplest topology,
   
• Arbitrated loop (FC-AL). In this design, all devices are in a loop or ring, similar to token ring networking. Adding or removing a device from the loop causes all activity on the loop to be interrupted. The failure of one device causes a break in the ring. Fibre Channel hubs exist to connect multiple devices together and may bypass failed ports. A loop may also be made by cabling each port to the next in a ring. Often an arbitrated loop between two ports will negotiate to become a P2P connection, but this is not required by the standard.
   
• Switched fabric (FC-SW). All devices or loops of devices are connected to Fibre Channel switches, similar conceptually to modern Ethernet implementations. The switches manage the state of the fabric, providing optimized interconnections. Very limited security is available in today's fibre channel switches