| LAN | Local Area Network. A network that interconnects PCs, terminals, workstations, servers, printers and other peripherals at a high speed over short distances (usually within the same floor or building). Various LAN standards have been developed, with Ethernet as the most widely used. |
| LANE | Local Area Network Emulation. A technique that specifies the interfaces and protocols needed for providing LAN-supported functionality and connectivity in an ATM environment, so that legacy protocols can be interoperable with the ATM protocols, interfaces and devices. |
| LAPD | Link Access Procedure D |
| LB | Leaky Bucket |
| LD | LAN Destination |
| LE | LAN Emulation |
| LE_ARP | LAN Emulation Address Resolution Protocol. LAN Emulation ARP. The ARP used in LAN Emulation for binding a requested ATM address to the MAC address. |
| LEC | LAN Emulation Client. Typically located in an ATM end system (i.e. ATM host, LAN switch), its task is to maintain address resolution tables and forward data traffic. It is uniquely associated with an ATM address. |
| LEC | Local Exchange Carrier. An intra-LATA communication services provider. |
| LECID | LAN Emulation Client Identifier |
| LECS | LAN Emulation Configuration Server. A server whose main function is to provide configuration information to a LEC (such as the ELAN it belongs to or its LES). |
| LES | LAN Emulation Server. A server which provides support for the LAN emulation address resolution protocol (LE-ARP). The LECs register their own ATM and MAC addresses with the LES. A LES is uniquely identified by an ATM address. |
| LIJP | Leaf Initiated Join Parameter |
| LIV | Link Integrity Verification |
| LLATMI | Lower Layer ATM Interface |
| LLC | Logical Link Control. The upper-half of the Data Link Layer in LANs that performs error control, broadcasting, multiplexing and flow control functions (see also MAC). |
| LMI | Local Management Interface. An ITU-T-defined interface to provide an ATM end-system user with network management information (see also ILMI). |
| LOC | Loss of Cell delineation |
| LOF | Loss of Frame |
| LOS | Loss of Signal |
| LSB | Least Significant Bit |
| LSR | Leaf Setup Request |
| LT | Lower Tester |
| LTH | Length Field |
| MA | Maintenance and Adaptation |
| MAC | Medium Access Control. A set of protocols that are (the lower) part of the Data Link Layer and consist the basis of the IEEE LAN specifications. Generally, MAC determines the way devices can transmit in a broadcast network (see also LLC). |
| MAN | Metropolitan Area Network. A term to describe a network that provides regional connectivity within a metropolitan area (such as a city). MANs are classified to be between LANs and WANs. |
| MBS | Maximum Burst Size. A traffic parameter that specifies the maximum number of cells that can be transmitted at the peak rate (PCR). |
| MCR | Minimum Cell Rate. A parameter that gives the minimum rate that cells can be transmitted by a source over a virtual connection (VC). |
| MCTD | Maximum Cell Transfer Delay. As the name suggests it is the maximum CTD over a given QoS class. |
| ME | Mapping Entity |
| MIB | Management Information Base. A data structure that defines objects for referencing variables such as integers and strings. In general, it contains information regarding network's management and performance, i.e. traffic parameters (see also ILMI, AToMMIB). |
| MID | Multiplex Identification. A 10-bit field in the AAL3/4 SAR-PDU header for identifying the different CPCS-PDUs multiplexed over the same VCC. |
| MIN | Multistage Interconnection Network. A switch fabric built from switching elements organized in series and/or in parallel, for providing physical connections between the inputs and the outputs of a switch. |
| MIR | Maximum Information Rate |
| MMF | Multimode Fiberoptic cable |
| MPEG | Motion Picture Experts Group. A video technology standard that specifies the digital encoding, transmission and decoding protocols, capable of presenting VCR quality motion video. |
| MPOA | Multiprotocol Over ATM. A set of standards to support, other than IP, (distributed) routing protocols. Developed on top of LANE and NHRP it willl support switches, route servers and hosts all attached to an ATM network. |
| MRCS | Multi-rate Circuit Switching |
| MS | Meta Signaling |
| MSAP | Management Service Access Point |
| MSB | Most Significant Bit |
| MSN | Monitoring Cell Sequence Number |
| MSVC | Meta-signaling Virtual Channel |
| MT | Message Type |
| MTP | Message Transfer Part |
| MTU | Message Transfer Unit |
| N-ISDN | Narrowband Integrated Services Digital Network |
| NDIS | Network Driver Interface Specification. Generic name for a device driver for a NIC, which is independent of any hardware or software implementation. |
| NE | Network Element |
| NEBIOS | Network Basic Input/Output System |
| NHRP | Next Hop Resolution Protocol. A protocol proposed to be used for ATM address resolution based on Classical IP. In particular if an address request cannot be served by a node it is forwarded to the next server-node on the path to the destination until finally the ATM-IP address mapping can be accomplished. |
| NMS | Network Management System. Set of OAM&P functions for setting the required hardware and software parameters used in managing a network. |
| NNI | Network to Network Interface |
| NP | Network Performance |
| NPC | Network Parameter Control. Traffic management mechanism (performed at the NNI) exercised by a network for traffic received by another network. |
| NRM | Network Resource Management |
| NSAP | Network Services Access Point. In the OSI environment it is the SAP between the network and the transport layers, which identifies a DTE by a unique address. |
| NSP | Network Service Provider |
| NSR | Non-Source Routed |
| NT | Network Termination |
| OAM | Operations and Maintenance. Set of administrative and supervisory actions regarding network performance monitoring, failure detection and system protection. Special-type cells are used to carry OAM-related information. |
| ODI | Open Data-Link Interface |
| OLI | Originating Line Information |
| OOF | Out of Frame |
| OPCR | Original Program Clock Reference |
| OSI | Open Systems Interconnection. The OSI Reference Model introduced by the International Organization for Standardization (ISO) consists of 7 layers, each specifying the protocols and functions required for two nodes to communicate using the underlying network infrastructure (physical medium, switches, routers, bridges, multiplexers, intermediate nodes). |
| OSID | Origination Signaling Identifier |
| OSPF | Open Shortest Path First |
| OUI | Organization Unique Identifier. |
| OUI | Organizational Unit Identifier. |