IBM SAN16B-2 User Guide - Page 78

local area network (LAN). A network that connects several devices into a limited area (such as a single building or campus) and that can be connected to a larger network. logical unit number (LUN). An identifier used on a SCSI bus to distinguish among devices (logical units) with the same SCSI ID. long wavelength (LWL). A type of fiber optic cabling that is based on 1300 mm lasers and supports link speeds of 1.0625 Gbps. Can also refer to the type of GBIC or SFP. See also short wavelength. loop. A configuration of devices that are connected to the fabric by way of a fabric loop port (FL_port) interface card. loop circuit. A temporary bidirectional communication path established between loop ports (L_ports). loop failure. Loss of signal within a loop for any period of time, or loss of synchronization for longer than the timeout value. loop_ID. A hexadecimal value representing one of the 127 possible arbitrated loop physical address (AL_PA) values in an arbitrated loop. loop initialization. The logical procedure used by a loop port (L_port) to discover its environment. Can be used to assign arbitrated loop physical address (AL_PA) addresses, detect loop failure, or reset a node. loop initialization primitive (LIP). The signal used to begin initialization in a loop. Indicates either loop failure or resetting of a node. looplet. A set of devices connected in a loop to a port that is a member of another loop. loop master timeout value (LM_TOV). The minimum time that the loop master waits for a loop initialization sequence to return. loop mode. One of the modes for a loop port (L_port). An L_port is in loop mode when it is in an arbitrated loop and is using loop protocol. An L_port in loop mode can also be in participating mode or nonparticipating mode. See also loop port, fabric mode, participating mode, and nonparticipating mode. loop port (L_port). A node port (NL_port) or fabric port (FL_port) that has arbitrated loop capabilities. An L_port can be either in fabric mode or loop mode. See also fabric mode , loop mode, nonparticipating mode, and participating mode. loop port state machine (LPSM). The logical entity that performs arbitrated loop protocols and defines the behavior of loop ports (L_ports) when they require access to an arbitrated loop. L_port. See loop port. 56 SAN16B-2 Installation, Service, and User's Guide LPSM. See loop port state machine. LSAN. Logical storage area network. An LSAN enables device and storage connectivity that spans two or more fabrics. LSR. Link state record. LSU. Link state update. LUN. See logical unit number. LWL. See long wavelength. M management information base (MIB). A simple network management protocol (SNMP) structure to help with device management, providing configuration and device information. master port. As relates to trunking, the port that determines the routing paths for all traffic flowing through the trunking group. One of the ports in the first inter-switch link (ISL) in the trunking group is designated as the master port for that group. See also ISL Trunking. MIB. See management information base. multicast. The transmission of data from a single source to multiple specified node ports (N_ports), as opposed to all the ports on the network. See also broadcast and unicast. multimode. A fiber optic cabling specification that allows up to 500 m (1640.5 ft) between devices. N name server. Frequently used to indicate Simple Name Server. See also simple name server. NEMA. National Electrical Manufacturers Association. network time protocol (NTP). An Internet standard protocol that provides synchronization of computer clock times in a network with times provided by radio or atomic clocks on the Internet. NL_port. See node loop port. node. A Fibre Channel device that contains a node port (N_port) or node loop port (NL_port). node loop port (NL_port). A node port that has arbitrated-loop capabilities. Used to connect an equipment port to the fabric in a loop configuration through an FL_Port. node name. The unique identifier for a node, communicated during login and port discovery.