IBM SAN16B-2 User Guide - 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. 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 52 SAN16B-2 Installation, Service, and User's Guide