gloss_L

L

LAN Manager.

LAN Manager was Microsoft's early model of a network operating system based on OS/2. It used NetBEUI or TCP/IP network protocols. LAN Manager supports DOS, Windows, OS/2, and Macintosh clients . Through LAN Manager for Unix, it offered connections to various Unix hosts .

LAN Server.

LAN Server is IBM's network operating system that is based on the OS/2 operating system and the NetBIOS network protocol. LAN Server supports DOS, Windows, OS/2, and Macintosh clients.

LANtastic.

LANtastic is Artisoft's peer-to-peer, NetBIOS-based network operating system. It supports DOS, Windows, OS/2, Macintosh, and Unix clients.

latency.

Signal delay, especially that resulting from transmission and processing.

leased line.

A leased line is a transmission line reserved by a communications carrier for the private use of a customer. Examples of leased-line services are 56Kbit/sec or T1 lines.

line of sight.

Laser, microwave, and some infrared transmission systems require that no visual obstructions exist in the path between the transmitter and receiver. This direct path is called the line of sight.

local area network (LAN).

A LAN is a group of computers, each equipped with the appropriate network adapter and software and connected by cable (or wireless links), that share applications, data, and peripherals. It typically spans a single building or campus.

Local Area Transport (LAT).

LAT is Digital Equipment's protocol suite for connecting terminals to an Ethernet network. Because LAT lacks a Network layer, it must be bridged in an enterprise network, not routed.

LocalTalk.

LocalTalk is one of Apple's Physical-layer standards. It transmits data at 230Kbits/sec using Carrier Sense Multiple Action with Collision Avoidance (CSMA/CA) over unshielded twisted-pair wire.

Logical Link Control (LLC).

OSI Layer 2, the Data-link layer, is divided into the Logical Link Control and the Media Access Control sublayers . LLC, which is the upper portion, handles error control, flow control and framing of the transmission between two stations . The most widely implemented LLC protocol is the IEEE 802.2 standard.

Logical Unit (LU).

IBM's LU suite of protocols govern session communication in an SNA network. LU1, LU2, and LU3 provide control of host sessions. LU4 supports host-to-device and peer-to-peer communication between peripheral nodes. LU6.2 is the peer-to-peer protocol of APPC. LU7 is similar to LU2.

LU

A Logical Unit is IBM's term for a communications session between physical devices such as computers, printers, or terminals. Some physical devices can simultaneously run multiple LUs. The various LUx session types define the communications protocols used to attach various logical units to an SNA network. LU1 defines communication with text printers. LU2 communicates with 3270-family terminals. LU3 communicates with 3270-family printers. LU4 and LU5 are no longer in use. LU6 supports communications between application programs. LU6.1 assumes that at least one physical device is a mainframe running IBM's CICS or IMS (Information Management System) software, and LU6.2 defines peer-to-peer communication between application software. LU7 defines communication with 5250-family terminals. See IBM 3270, IBM 5250, LU6.2.

LU6.2

LU6.2 is a type of logical unit that supports communication between application programs in an SNA-based network. LU6.2-compliant devices operate as peers within the network and can perform multiple simultaneous transactions over the network. LU6.2 devices can also detect and correct errors. The LU6.2 definition provides a common API for communicating with and controlling compliant devices. APPC is often used to refer to the LU6.2 architecture or to specific LU6.2 features. See APPC, LU.