HP StorageWorks XPath OS 7.4.X Command Reference Guide (AA-RVHCC-TE, September 2005)

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data word A type of transmission word that occurs within frames. The frame header, data field, and CRC
all consist of data words. See also frame, ordered set, transmission word.
datagram A Class 3 Fibre Channel service that allows data to be sent quickly to devices attached to the
fabric, without receipt confirmation.
DCE Data communications equipment. Usually refers to a modem.
dedicated simplex A connection method that permits a single N_Port to simultaneously initiate a session with one
N_Port as an initiator and have a separate Class 1 connection to another N_Port as a
recipient.
defined zone
configuration
The set of all zone objects defined in the fabric. Can include multiple zone configurations. See
also enabled zone configuration, zone configuration.
DHCP Dynamic Host Configuration Protocol.
DHCPD Dynamic Host Configuration Protocol daemon.
digital certificate An electronic document issued by a CA (certificate authority) to an entity, containing the
public key and identity of the entity. Entities in a secure fabric are authenticated based on
these certificates. See also authentication, CA, public key.
disparity The proportion of ones and zeroes 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 zeroes.
DLS Dynamic load-sharing. Dynamic distribution of traffic over available paths. Allows for
recomputing of routes when an Fx_Port or an E_Port changes status.
domain controller A domain controller (or embedded port) communicates with and gets updates from other
switches’ embedded ports. The well-known address is fffcdd, where dd = domain number.
domain ID A unique identifier for all switches in a fabric, used in routing frames. Usually automatically
assigned by the principal switch but can be assigned manually.
DTE Data terminal equipment. Usually refers to a terminal.
DWDM Dense wave division multiplexing. Allows more wavelengths to use the same fiber. See also
WDM.
E_D_TOV Error-detect timeout value. The minimum amount of time a target waits for a sequence to
complete before initiating recovery. Can also be defined as the maximum time allowed for a
round-trip transmission before an error is declared. See also R_A_TOV, RR_TOV.
E_Port Expansion port. A type of switch port that can be connected to an E_Port on another switch to
create an ISL. See also ISL.
ECCN Export classification control number. A government classification of encryption. For example,
SSH is in the high-encryption category (number 5x02) and therefore has certain restrictions
regarding its transfer.
EE_Credit End-to-end credit. The number of receive buffers allocated by a recipient port to an originating
port. Used by Class 1 and 2 services to manage frame exchange across the fabric, between
source and destination. See also BB_Credit, end-to-end flow control.
EIA rack A storage rack that meets the standards set by the Electronics Industry Alliance (EIA).
ELP Exchange link parameters.
ELS Extended link service. ELSs are sent to the destination N_Port to perform the requested function
or service. ELS is a Fibre Channel standard that is sometimes referred to as Fibre Channel
Physical (FC_PH) ELS.
EM Environmental monitor. Monitors FRUs and reports failures.
embedded port An embedded port (or domain controller) communicates and get updates from other switches’
embedded ports. The well-known address is fffcdd, where dd = domain number.
EMI Electromagnetic interference.
emulex A brand of host bus adapter (HBA).
enabled zone
configuration
The currently enabled configuration of zones. Only one configuration can be enabled at a
time. See also defined zone configuration, zone configuration.