Fibre Channel Interface

Fibre channel is a type of SCSI hard drive technology used in high-end systems with multiple hard drives installed. Using optical fiber to connect devices, fibre channel supports full-duplex data transfer rates up to 100 MB per second. Fibre channel is mostly found in servers and may eventually replace SCSI as the most popular interface for high-performance storage systems. As many as 126 devices can be connected to a single fibre channel bus and fibre channel is also faster than SCSI. Massive storage solutions are possible with fibre channel, but it is too expensive to be used by the average desktop PC.

Layers of Fibre Channel

The five fibre channel layers are:

• FC0

  Physical layer

• FC1

  Data link layer

• FC2

  Network layer

• FC3

  Auxilary layer

• FC4

  Application layer

Fibre Channel Topologies

There are three fibre channel topologies: Point-to-Point, Arbitrated Loop and Fabric.

Point-to-Point

Consists of two devices connected directly together. This is the least complex of the topologies. The transmit link of one device goes to the receive link of the other fibre device, and vice versa.

Arbitrated Loop

Arbitrated Loop is the most complicated of the fibre channel topologies and is also the most widely used topology. With arbitrated loop, media is shared between fibre devices. It allows for up to 127 ports without the use of a fabric switch.

Fabric

Fabric topology requires the purchase of a fabric switch. As many as 224 devices can be connected using the fabric topology and the media is not shared, so the devices can communicate at the same time.