Compaq AA-RHGWB-TE manual Fibre Channel Overview, Basic Fibre Channel Terminology

•Wwidmgr User’s Manual

6.2Fibre Channel Overview

Fibre Channel supports multiple protocols over the same physical interface. Fibre Channel is primarily a protocol-independent transport medium; therefore, it is independent of the function that it is used for.

The TruCluster Server uses the Fibre Channel Protocol (FCP) for SCSI to use Fibre Channel as the physical interface.

Fibre Channel, with its serial transmission method overcomes the limitations of parallel SCSI by providing:

•Data rates of 100 MB/sec, 200 MB/sec, and 400 MB/sec

•Support for multiple protocols

•Better scalability

•Improved reliability, serviceability, and availability

Fibre Channel uses an extremely high-transmit clock frequency to achieve the high data rate. Using optical fibre transmission lines allows the high-frequency information to be sent up to 40 km, the maximum distance between transmitter and receiver. Copper transmission lines may be used for shorter distances.

6.2.1 Basic Fibre Channel Terminology

The following list describes the basic Fibre Channel terminology:

Frame	All data is transferred in a packet of information
	called a frame. A frame is limited to 2112 bytes. If
	the information consists of more than 2112 bytes, it
	is divided up into multiple frames.
Node	The source and destination of a frame. A node
	may be a computer system, a redundant array of
	independent disks (RAID) array controller, or a disk
	device. Each node has a 64-bit unique node name
	(worldwide name) that is built into the node when it
	is manufactured.
N_Port	Each node must have at least one Fibre Channel
	port from which to send or receive data. This node
	port is called an N_Port. Each port is assigned a
	64-bit unique port name (worldwide name) when it

6–4Using Fibre Channel Storage