IBM T400 Fibre Channel Attachment, Supported Topologies, Type of Topology, Direct Connection

Fibre Channel Attachment

Attention: A Class I laser assembly, in the optical transceiver, is mounted on the Ultrium Fibre Channel electronics card. This laser assembly is registered with the Department of Health and Human Services and is in compliance with IEC825.

To communicate with a server, the Ultrium 2 Tape Drive has one Fibre Channel interface (also called a port). In accordance with the standards of the American National Standards Institute (ANSI), the port runs Fibre Channel Protocol (which includes SCSI commands on the Fibre Channel) with ANSI-defined Fibre Channel Tape Support. The method by which the drive and server communicate is determined by the type of topology in which they reside and the type of connection that you choose.

Supported Topologies

The Ultrium 2 Tape Drive can be attached in a two-node configuration, either directly to a switch as a public device (switched fabric) or directly to a host bus adapter (HBA) as a private device. It can do so in a Point-to-Point topology (through an N_port or F_port) or Arbitrated Loop topology (through an L_port or FL_port).

Unless you set the drive to force an explicit configuration (by using the FC configuration/status connector; see “Step 4. Change the Link Services of the Drive (optional)” on page 24), the Ultrium 2 Tape Drive automatically configures to an L_port or an N_port when it boots. The type of port to which it configures depends on whether the drive recognizes the connection as a loop or a point-to-point connection:

vAn L_port supports a Fibre Channel Arbitrated Loop connection to an NL_port or FL_port.

vAn N_port supports direct connection to another N_port or to an F_port (for example, a director-class switch) in a point-to-point topology.

Regardless of the port to which you connect the drive, it automatically configures to a public device (through an F_port or FL_port to a switch) or to a private device (through an N_port or L_port by using direct attachment to a server).

Table 3 lists the topologies in which the Ultrium 2 Tape Drive can operate, the Fibre Channel server connections that are available, and the port (NL, N, FL, or F) through which communication must occur.

Table 3. Choosing the port for your topology and Fibre Channel connection

	Type of Fibre Channel Connection to Server
Type of Topology
	Direct Connection	Switched Fabric
	(Private)	(Public)
Fibre Channel-Arbitrated	L_Port	FL_Port
Loop
(can be Two-Node Arbitrated
Loop or Two-Node Switched
Fabric Loop; is limited to two
nodes)
Point-to-Point	N_Port	F_Port
(two nodes)

6IBM TotalStorage LTO Ultrium 2 Tape Drive