Choosing The Port For Your Topology And - IBM System Storage TS3310 Setup And Operator Manual

adapter (HBA) as a private device. It can connect as a public device in a switched
fabric topology (through an F_port) or connect using Arbitrated Loop topology
(through an L_port or FL_port).
The Ultrium 3 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:
v An L_Port supports a Fibre Channel Arbitrated Loop connection to an NL_port
or an FL_port.
v An N_Port supports a point-to-point connection to an F_port (for example, a
director-class switch) in a switched fabric 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 L_port by using direct attachment to a server).
The table below lists the topologies in which the Ultrium Tape Drive can operate,
the Fibre Channel server connections that are available, and the port through
which communication must occur.
Table 2-4. Choosing the port for your topology and Fibre Channel connection
Type of Topology
Fibre Channel Aribitrated
Loop(can be Two-Node
Arbitrated Loop or
Two-Node Switched Fabric
Loop; is limited to two
nodes)
Switched fabric (two nodes)
LUN Assignments
The logical unit number (LUN) for the Sequential Access device is always LUN 0
of the drive, and the LUN for the Medium Changer device is always LUN 1 (all
other LUNs are invalid addresses). These devices are compatible with the SCSI-3
standard. For information about the SCSI commands for the tape drive and the
library, see the IBM TotalStorage LTO Ultrium Tape Drive SCSI Reference and the IBM
System Storage TS3310 Tape Library SCSI Reference.
Note: The Medium Changer SCSI ID is the same as the SCSI ID for the control
path drive. You can enable additional drives to optionally provide Medium
Changer (LUN 1) addressing by configuring more than one logical library or
by enabling additional control paths (see "Determining the Number of
Logical Libraries (Partitions)" on page 2-1.
Using World Wide Names
Normally, blocks of World Wide Name (WWN) addresses are assigned to
manufacturers by the IEEE Standards Committee, and are built into devices during
manufacture. In the case of the library, however, it assigns World Wide Node
Names and World Wide Port Names to the drives. This technique is referred to as
persistent world wide names. Potential drive slots are each assigned a WWN
which does not change when a drive is swapped or replaced.
Type of Fibre Channel Connection to Server
Direct Connection(Private)
L_Port
N/A
Chapter 2. Installation Planning
Switched Fabric(Public)
FL_Port
F_Port
2-7