IBM System Storage TS3100, Setup, Operator, And Service Manual

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Fibre Channel Interface
Fibre Channel allows for an active intelligent interconnection scheme, called a
Fabric, to connect devices. Everything between the ports on Fibre Channel is called
the Fabric. The Fabric is most often a switch or series of switches that takes the
responsibility for routing.
The library allows the selection of the following Fibre channel port behaviors:
v
LN Port: (default setting) - an automatic configuration that tries arbitrated loop
first, then switched fabric
v L Port - arbitrated loop
v N Port - point to point protocol in a switched fabric topology
Cables and Speeds
Ultrium 3, Ultrium 4, Ultrium 5, and Ultrium 6 Fibre Channel tape drives use LC
duplex fiber optics cables.
The maximum distances that the library supports on a Fibre Channel link is
determined by the link speed, the type of fiber (50-micron or 62.5-micron), and the
device to which the library is attached.
If the library attaches to an HBA (Host Bus Adapter), refer to the distances that are
supported by the HBA. If the library attaches to a switch, the supported distances
are:
v
For a multi-mode 50-micron cable:
– 1-Gbit link speed = up to 500 m (1640 ft)
– 2-Gbit link speed = up to 300 m (984 ft)
– 4-Gbit link speed = up to 175 m (574 ft)
– 8-Gbit link speed = up to 150 m (492 ft)
v For a multi-mode 62.5-micron cable:
– 1-Gbit link speed = up to 300 m (984 ft)
– 2-Gbit link speed = up to 90 m (295 ft)
– 4-Gbit link speed = up to 50 m (164 ft)
– 8-Gbit link speed = up to 21 m (68 ft)
Note:
Minimum distance for both 50 micron and 62.5 micron is 2 m (6 ft).
Using Zoning to Isolate Devices and Enhance Security
For security reasons, it is important to limit the devices that a server or servers can
recognize or access. Also, some performance configurations and SAN
configurations can result in a device being seen multiple times from the same
server. For example, if you have two HBAs from the same server connected to an
Ultrium Tape Drive in the library, the drive will be detected and appear as two
logical devices. That is, there will be two special files for one physical device.
Zoning can address these issues.
Zoning allows you to partition your SAN into logical groupings of devices so that
each group is isolated from the other and can only access the devices in its own
group. Two types of zoning exist: hardware zoning and software zoning. Hardware
zoning is based on physical fabric port number. Software zoning is defined with a
World Wide Node Name (WWNN) or World Wide Port Name (WWPN). While
zoning can be reconfigured without causing an outage, some zoning configurations
can become complicated. The advantage of the library's WWNN implementation is
Chapter 3. Installation Planning
3-11
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