IBM SAN16B-2 - TotalStorage Express Model Switch User And Service Manual page 74

DB-9 connector. A 9–pin version of the RS–232C port
interface.
dc. Direct current.
defined zone configuration. The complete set of all
zone objects that are defined in the fabric. The defined
configuration can include multiple zone configurations.
See also enabled zone configuration and zone
configuration.
DHCP. Dynamic Host Configuration Protocol.
disparity. The proportion of ones and zeros in an
encoded character. Neutral disparity means an equal
number of each, positive disparity means a majority of
ones, and negative disparity means a majority of zeros.
DLS. See dynamic load sharing.
DMA. See direct memory access.
DNS. Distributed name server.
domain_ID. Unique identifier for the switch in a fabric.
Usually automatically assigned by the switch, but can
also be assigned manually. Can be any value between
1–239.
DRAM. See dynamic random access memory.
DTE. Data terminal equipment. Usually refers to a
terminal.
DWDM. Dense wavelength division multiplexing.
Allows more wavelengths to use the same fiber.
dynamic random access memory (DRAM). A
storage in which the cells require repetitive application
of control signals to retain stored data.
E
edge fabric. A single fabric that uses two or more
switches as a core to interconnect multiple edge
switches. Synonymous with dual-core fabric. See also
resilient core.
edge switch. A switch whose main task is to connect
nodes into the fabric. See also core switch.
E_D_TOV. See error detect timeout value.
EE_credit. See end-to-end credit.
effective zone configuration. The particular zone
configuration that is currently in effect. Only one
configuration can be in effect at once. The effective
configuration is built each time a zone configuration is
enabled.
EIA. Electronic Industries Alliance.
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SAN16B-2 Installation, Service, and User's Guide
EIA rack. A storage rack that meets the standards set
by the Electronics Industries Alliance (EIA).
electromagnetic compatibility (EMC). The design
and test of products to meet legal and corporate
specifications dealing with the emissions and
susceptibility to frequencies in the radio spectrum.
Electromagnetic compatibility is the ability of various
electronic equipment to operate properly in the intended
electromagnetic environment.
electromagnetic interference (EMI). Waves of
electromagnetic radiation, including but not limited to
radio frequencies, generated by the flow of electric
current.
electrostatic discharge (ESD). The flow of current
that results when objects having a static charge come
into close enough proximity to discharge.
ELP. Extended link parameters.
ELWL. See extra long wavelength.
EMC. See electromagnetic compatibility.
EMI. See electromagnetic interference.
enabled zone configuration. The currently enabled
configuration of zones. Only one configuration can be
enabled at a time. See also defined zone configuration
and zone configuration.
end port. A port on an edge switch that connects a
device to the fabric.
end-to-end credit (EE_credit). The number of receive
buffers allocated by a recipient port to an originating
port. Used by class 1 and class 2 services to manage
the exchange of frames across the fabric between
source and destination. See also end-to-end flow control
and buffer-to-buffer credit.
end-to-end flow control. Governs flow of class 1 and
class 2 frames between node ports (N_ports). See also
end-to-end credit.
E_port. See expansion port.
error. As applies to fibre channel, a missing or
corrupted frame, timeout, loss of synchronization, or
loss of signal (link errors). See also loop failure.
error detect timeout value (E_D_TOV). The time that
the switch waits for an expected response before
declaring an error condition. Adjustable in 1
microsecond increments from 2—10 seconds.
ESD. See electrostatic discharge.
exchange. The highest level Fibre Channel
mechanism used for communication between node