Fujitsu MAF3364FC, MAG3091FC, MAG3182FC manual FC-AL system configuration

1.3System Configuration

As the fibre channel mode, the ANSI standard defines three modes: Arbitrated Loop, Fabric and Point-to-Point. This drive supports Arbitrated Loop (FC-AL). Figure 1.4 shows an example of the system configuration.

Port B

Initiator

(Node-1)

Port A

Port B

Drive

(Node-4)

Port A

BC

BC

BC

BC

BC	Port B
	Drive
	(Node-2)
BC	Port A

BC	Port B
	Drive
	(Node-3)
BC
	Port A

Figure 1.4 FC-AL system configuration

The mode of connection of all devices to the fibre channel is called “node.” The drive and initiator correspond to the node shown in Figure 1.4. Each node has at least one port called “N- port.” In the FC-AL, a port is particularly called “node loop (NL) port.” The MAF3364FC and MAG series have two ports; one is connected to one FC-AL and a maximum of 126 NL ports can be connected to one loop.

(1)Loop configuration

One port incorporates a transmit circuit and receive circuit. Information is transmitted/received by differential signals via electric signal lines. This pair of signal lines is called a link. Since signals on a link are transmitted in one direction, wiring must be conducted so that it may form a loop connection on the system.

In the case of the FC-AL interface, information is transmitted/received via each node connected on a loop. Accordingly, if the power supply is off at a node connected to the loop or if interface signals cannot be transmitted/received normally, the loop will no longer function. To avoid such a nonconformity, a circuit called “port bypass circuit” is generally provided on the back plane of the system. BC in Figure 1.4 shows this port bypass circuit.

(2)Node addressing

Each node on the fibre channel loop is assigned its specific model number (SEL ID). The SEL ID of the drive is set at the signal level on the back plane through 7 signals from SEL_0 to

SEL_6 of the SCA interface connector (CN1). In signal bit weighting, SEL_6 is the MSB indicating 26 and SEL_0 is the LSB indicating 20.

The SEL ID setting of the drive ranges from #0(x‘00’) to #125(x‘7D’).

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