User`s guide

378 Implementing an Open IBM SAN
Port Bypass Circuit A circuit used in hubs and
disk enclosures to automatically open or close
the loop to add or remove nodes on the loop.
Private NL_Port An NL_Port which does not
attempt login with the fabric and only
communicates with other NL Ports on the same
loop.
Protocol A data transmission convention
encompassing timing, control, formatting and
data representation.
Public NL_Port An NL_Port that attempts login
with the fabric and can observe the rules of either
public or private loop behavior. A public NL_Port
may communicate with both private and public
NL_Ports.
Quality of Service (QoS) A set of
communications characteristics required by an
application. Each QoS defines a specific
transmission priority, level of route reliability, and
security level.
RAID Redundant Array of Inexpensive or
Independent Disks. A method of configuring
multiple disk drives in a storage subsystem for
high availability and high performance.
Raid 0 Level 0 RAID support - Striping, no
redundancy
Raid 1 Level 1 RAID support - mirroring,
complete redundancy
Raid 5 Level 5 RAID support, Striping with parity
Repeater A device that receives a signal on an
electromagnetic or optical transmission medium,
amplifies the signal, and then retransmits it along
the next leg of the medium.
Responder A Fibre Channel term referring to the
answering device.
Router (1) A device that can decide which of
several paths network traffic will follow based on
some optimal metric. Routers forward packets
from one network to another based on
network-layer information. (2) A dedicated
computer hardware and/or software package
which manages the connection between two or
more networks. See also: Bridge, Bridge/Router
SAF-TE SCSI Accessed Fault-Tolerant
Enclosures
SAN A Storage Area Network (SAN) is a
dedicated, centrally managed, secure information
infrastructure, which enables any-to-any
interconnection of servers and storage systems.
SAN System Area Network - term originally used
to describe a particular symmetric
multiprocessing (SMP) architecture in which a
switched interconnect is used in place of a
shared bus. Server Area Network - refers to a
switched interconnect between multiple SMPs.
SC Connector Subscriber Connector. A fiber
optic connector standardized by ANSI
TIA/EIA-568A for use in structured wiring
installations.
Scalability The ability of a computer application
or product (hardware or software) to continue to
function well as it (or its context) is changed in
size or volume. For example, the ability to retain
performance levels when adding additional
processors, memory and/or storage.
SCSI Small Computer System Interface - A set of
evolving ANSI standard electronic interfaces that
allow personal computers to communicate with
peripheral hardware such as disk drives, tape
drives, CD_ROM drives, printers and scanners
faster and more flexibly than previous interfaces.
The table below identifies the major
characteristics of the different SCSI version.
SCSI
Ver-
sion
Sig-
nal
Rate
MHz
Bus-
Width
(bits)
Max.
DTR
(MB/s
)
Max.
Num.
Devic
es
Max.
Cable
Lengt
h(m)
SCSI
-1
58576
SCSI
-2
58576
Wide
SCSI
-2
51610156
Fast
SCSI
-2
108107 6