IBM 2109 Model M12 User Manual page 85

redundant array of independent disks (RAID). A
collection of disk drives that appear as a single volume
to the server and are fault tolerant through mirroring or
parity checking.
registered state change notification (RSCN). A
switch function that allows notification of fabric changes
to be sent from the switch to specified nodes.
remote fabric. A fabric that spans across wide area
networks (WANs) by using protocol translation (a
process also known as tunneling) such as fibre channel
over asynchronous transfer mode (ATM) or fibre
channel over Internet protocol (IP).
remote procedure call (RPC). A facility that a client
uses to request the execution of a procedure call from a
server.
Remote Switch. A feature that runs on Fabric
operating system (OS) and enables two fabric switches
to be connected over an asynchronous transfer mode
(ATM) connection. This requires a compatible Fibre
Channel to ATM gateway, and can have a distance of
up to 10 km (6.214 mi) between each switch and the
respective ATM gateway.
request rate. The rate at which requests arrive at a
servicing entity. See also service rate.
resilient core. A single fabric that uses two or more
switches as a core to interconnect multiple edge
switches. Synonymous with dual-core fabric.
resource allocation timeout value (R_A_TOV). Used
to time out operations that depend on the maximum
possible time that a frame can be delayed in a fabric
and still be delivered. This value is adjustable in one
microsecond increments from 10 - 120 seconds.
resource recover timeout value (RR_TOV). The
minimum time a target device in a loop waits after a
loop initialization primitive (LIP) before logging out a
small computer systems interface (SCSI) initiator. See
also error detect timeout value and resource allocation
timeout value.
RISC. See reduced instruction set computer.
RLS probing. Read link status of the arbitrated loop
physical addresses (AL_PAs).
ro. Read only.
ROM. See read only memory.
route. As applies to a fabric, the communication path
between two switches. Can also apply to the specific
path taken by an individual frame, from source to
destination. See also Fibre Channel shortest path first.
routing. The assignment of frames to specific switch
ports, according to frame destination.
RPC. See remote procedure call.
R_RDY. See receiver ready.
RR_TOV. See resource recovery timeout value.
RS-232 port. A port that conforms to a set of Electrical
Industries Association (EIA) standards. Used to connect
data terminal equipment (DTE) and data
communications equipment (DCE) devices for
communication between components, terminals, and
modems. See also DB-9 connector, DCE port, and DTE
port.
RSCN. See registered state change notification.
RSH. Remote shell.
RTC. Real time clock.
rw. Read-write.
SAN. See storage area network.
SAN island. A group of storage devices and servers
connected to switches in a fabric.
SC. Standard connector.
SCSI. See small computer systems interface.
SCSI Enclosure Services (SES). A subset of the
small computer systems interface (SCSI) protocol used
to monitor temperature, power, and fan status for
enclosure devices.
SDRAM. See synchronous dynamic random access
memory.
Secure Fabric OS. An optionally-licensed software
product that runs on top of the Fabric OS and provides
customizable security restrictions through local and
remote management channels on a switch.
secure sockets layer (SSL). A security protocol that
provides communication privacy. SSL enables
client/server applications to communicate in a way that
is designed to prevent eavesdropping, tampering, and
message forgery.
sequence. A group of related frames transmitted in the
same direction between two node ports (N_ports).
SERDES. Serializer/deserializer.
service rate. The rate at which an entity can service
requests. See also request rate.
SES. See SCSI Enclosure Services.
SFP. See small form-factor pluggable.
short wavelength (SWL). A type of fiber optic cabling
that is based on 850 mm lasers and supports 1.0625
Gbps link speeds. Can also refer to the type of gigabit
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Glossary