IBM SC30-3681-08 Line switching. Synonym for circuit switching, Management interface LMI protocol

LES. LAN Emulation Server. A LAN Emulation Service component that resolves LAN Destinations to ATM Addresses.

line switching. Synonym for circuit switching.

link. The combination of the link connection (the transmission medium) and two link stations, one at each end of the link connection. A link connection can be shared among multiple links in a multipoint or token-ring con®guration.

link access protocol balanced (LAPB). A protocol used for accessing an X.25 network at the link level. LAPB is a duplex, asynchronous, symmetric protocol, used in point-to-point communication.

link-attached.(1) Pertaining to devices that are connected to a controlling unit by a data link. (2) Contrast with channel-attached. (3) Synonymous with remote.

link connection. (1) The physical equipment providing two-way communication between one link station and one or more other link stations; for example, a telecommunication line and data circuit-terminating equipment (DCE). (2) In SNA, synonymous with data circuit.

link level. (1) A part of Recommendation X.25 that de®nes the link protocol used to get data into and out of the network across the full-duplex link connecting the subscriber's machine to the network node. LAP and LAPB are the link access protocols recommended by the CCITT. (2) See data link level.

link-state.In routing protocols, the advertised information about the usable interfaces and reachable neighbors of a router or network. The protocol's topological database is formed from the collected link-state advertisements.

link station. (1) The hardware and software components within a node representing a connection to an adjacent node over a speci®c link. For example, if node A is the primary end of a multipoint line that connects to three adjacent nodes, node A will have three link stations representing the connections to the adjacent nodes. (2) See also adjacent link station (ALS).

local. (1) Pertaining to a device accessed directly without use of a telecommunication line. (2) Contrast with remote. (3) Synonym for channel-attached.

local area network (LAN). (1) A computer network located on a user's premises within a limited geographical area. Communication within a local area network is not subject to external regulations; however, communication across the LAN boundary may be subject to some form of regulation. (T) (2) A network in which a set of devices are connected to one another for communication and that can be connected to a

larger network. (3) See also Ethernet and token ring. (4) Contrast with metropolitan area network (MAN) and wide area network (WAN).

local bridging. A function of a bridge program that allows a single bridge to connect multiple LAN segments without using a telecommunication link. Contrast with remote bridging.

local management interface (LMI). See local

management interface (LMI) protocol.

local management interface (LMI) protocol. In NCP,

a set of frame-relay network management procedures and messages used by adjacent frame-relay nodes to exchange line status information over DLCI X©00©. NCP supports both the American National Standards Institute (ANSI) and International Telegraph and Telephone Consultative Committee (ITU-T/CCITT) versions of LMI protocol. These standards refer to LMI protocol as link integrity veri®cation tests (LIVT).

locally administered address. In a local area network, an adapter address that the user can assign to override the universally administered address. Contrast with universally administered address.

logical channel. In packet mode operation, a sending channel and a receiving channel that together are used to send and receive data over a data link at the same time. Several logical channels can be established on the same data link by interleaving the transmission of packets.

logical link. A pair of link stations, one in each of two adjacent nodes, and their underlying link connection, providing a single link-layer connection between the two nodes. Multiple logical links can be distinguished while they share the use of the same physical media connecting two nodes. Examples are 802.2 logical links used on local area network (LAN) facilities and LAP E logical links on the same point-to-point physical link between two nodes. The term logical link also includes the multiple X.25 logical channels that share the use of the access link from a DTE to an X.25 network.

logical link control (LLC). The data link control (DLC) LAN sublayer that provides two types of DLC operation for the orderly exchange of information. The ®rst type is connectionless service, which allows information to be sent and received without establishing a link. The LLC sublayer does not perform error recovery or ¯ow control for connectionless service. The second type is connection-oriented service, which requires establishing a link prior to the exchange of information. Connection-oriented service provides sequenced information transfer, ¯ow control, and error recovery.

logical link control (LLC) protocol. In a local area network, the protocol that governs the exchange of transmission frames between data stations independently of how the transmission medium is

702MRS V3.2 Software User's Guide