L A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T| U| V| W| X| Y| Z| Numerical Listing| LAN (Local-Area Network) A user-owned and user-operated data transmission facility connecting a number of communicating devices, e.g., computer, terminals, word processors, printers and mass storage units, within a single building or campus of buildings. Uses gateways or communications servers to connect with other hosts. Examples are Ethernet, AT&T’s StarLAN and IBM’s Token Ring Network. LAN Bridging Multiple physical local-area networks (LANs) can be connected with local- or wide-area connections to support a single logical LAN environment. LAN Performance Monitor A tool or toolset (hardware/software) to allow local or remote monitoring of local-area network traffic and problems. LAP-B (Link Access Procedure — Balanced) A subset of High-Level Data Link Control used in Open Systems Interconnection to control Layer 2 functions. LAP-D (Link Access Procedure — D channel) A data link layer procedure using D channel communications, typical of Integrated Services Digital Network. TOP OF PAGE Laser A device that emits a highly coherent beam of light. The name stands for light amplification by stimulated emission or radiation. A typical laser has an active medium, which emits light, and a cavity structure, which selects certain wavelengths and directions for the emitted light. LATA (Local Access and Transport Area) A LATA is a local telephone network area controlled and operated by a local exchange carrier, e.g., one of the Bell operating companies. A LATA is one of 193 local telephone company serving areas generally encompassing the largest standard metropolitan statistical areas. Circuits/calls within a LATA (intra-LATA) are generally the sole responsibility of the local exchange carrier, while interexchange carriers, such as AT&T or MCI, handle circuits/calls that cross LATA boundaries (inter-LATA). Layer In the Open Systems Interconnection (OSI) reference model, refers to a collection of related network-processing functions that comprise one level of a hierarchy of functions. Lead Time A span of time required to perform an activity. In a production and inventory control context, the activity is normally the procurement of materials or product from either an outside supplier or a company’s own manufacturing facility. The individual components of any given lead time can include some or all of the following: order preparation time, queue time, move or transportation time, receiving and inspection time. Leased Line A line rented exclusively to one customer for voice or data communications; also called a private line, tie line or dedicated facility . Least Total Cost A dynamic lot sizing technique that calculates the order quantity by comparing the carrying cost and the setup (or ordering) costs for various lot sizes and selects the lot where comparisons are not nearly equal. LEC (Local Exchange Carrier) An LEC is the carrier or local telephone company that handles intra-LATA (Local Access and Transport Area) traffic, e.g., one of the 23 Bell operating companies or any of the independent telephone companies. TOP OF PAGE LEN (Low-Entry Networking) An IBM networking architecture introduced in 1986. It is an Advanced Program-to-Program Communications application and a potential low-end alternative to Systems Network Architecture (SNA). SNA is complex and, for department environments, difficult to manage. LEN uses Synchronous Data Link Control as the backbone protocol and possesses a self-contained network management capability that is less comprehensive than IBM’s traditional methods but is much easier to set up and operate. Lessee An entity that contractually obtains use of equipment in return for payments over a specified time. Lessor An entity that conveys possession of specified property to a lessee for a period of time. Library A data management system for documents, frequently, though not necessarily, organized in a hierarchy of folders and drawers. Also called file cabinet. Link Layer The logical entity in the Open Systems Interconnection (OSI) model concerned with transmission of data between adjacent network nodes. It is the second layer in the OSI model, between the physical and the network layers. TOP OF PAGE Linpack An early benchmark for scientific applications now replaced by the SPECmark. Load Balancing The ability of processors to schedule themselves to ensure that all are kept busy while instruction streams are available. LOB (Line of Business) An organizational unit within IBM’s new structure. Local Loop That part of a communications circuit between the subscriber’s equipment and the equipment in the local central office. Location Broker Middleware that automatically matches a client query with whichever server has the most suitable services, data and computing resources to accomplish the task. Lock A means of preventing two users from trying to update the same data simultaneously. Look and Feel The appearance and behavior of a graphical user interface to the end user (who sees it as part of an application), determined by the tools and style guide provided by the vendor (and by whether the software developer obeys these guidelines). TOP OF PAGE Loosely Coupled Multiprocessing A configuration of several processors, each with its own memory, that execute user and operating system code independently. Lower-CASE Tool A tool for application generation rather than application modeling. LU (Logical Unit) IBM’s term for a logical node that is the user’s "port" into a Systems Network Architecture network. LU 1 is a high-performance print data stream and a 3270 data stream. LU 6 enables host-to-host data exchange, and provides a peer-to-peer data stream. TOP OF PAGE LU 6.2 (Logical Unit Type 6.2.) An IBM Systems Network Architecture (SNA) protocol. LU 6.2 is a strategic device-independent, process-to-process protocol; it also supports asynchronous (store-and-forward) networking. It provides the facilities for peer-to-peer communications between two programs. Among other things, this means that programs and small/midrange computer systems can use LU 6.2 (along with PU 2.1) to establish and control sessions with each other, without host mainframe participation. When LU 6.2 is installed in devices such as PCs and cluster controllers, required functionality, such as multiple sessions among those devices and System/370 hosts becomes available. Comments? Questions? Entire contents Copyright © 1997, 1998 by Gartner Group, Inc. All rights reserved. Reproduction of this publication in any form without prior written permission is forbidden. 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