Microwave frequency band in the range of 1 - 2 GHz that corresponds to wavelength from 30 cm to 15 cm. 

Layer 2 Forwarding. A Layer 2 tunneling protocol developed by Cisco.
Also see tunnel and VPN.

Layer 2 Tunneling Protocol. A standard Layer 2 tunneling protocol that was developed from earlier protocols, i.e. L2F and PPTP. L2TP is used in VPN.
Also see tunnel and VPN.

Portable computer. A.k.a. notebook.

Local Area Network. A group of interconnected computers and/or devices within limited area like a house or an office building. LAN can be implemented using various physical media, i.e. copper wires (twisted pair), coaxial cable, fiber optic, microwave, and radio wave. Several LAN technologies are in use today. The most popular are Ethernet for wired LAN and and Wi-Fi for wireless LAN.
Also see PAN, MAN, WAN.

A gathering of people with common interest especially in popular game, that is held to play the game over a Local Area Network (LAN). In most cases, the event was organized informally by a friend or a neighbor and uses a small network. But there are also periodic world multiplayer game competitions involving hundreds participants over a very big LAN.

LAN Emulation. The encapsulation of Ethernet frames in LANE packets and their conversion into ATM cells for the purpose of interconnecting Ethernet LANs over ATM network.
Also see Ethernet, frame, and ATM.

The delay from the transmit request to the actual transmit as a result of packet processing (i.e. store, analyze, and forward).
Also see jitter and throughput.

Lightweight Directory Access Protocol. A standard protocol for Internet telephony (VoIP) directory services. Directories are required to ensure interoperability between the Internet and the PSTN.
Also see VoIP and PSTN.

Light Extensible Authentication Protocol. An implementation of EAP and 802.1x for wireless networks that was developed by Cisco. LEAP uses preshared keys and MS-CHAP protocol to authenticate client and server to each other.
Also see EAP and CHAP.

Local Exchange Carrier. Another name for local telephone (telecom) operator.
Also see CLEC and ILEC.

Low Frequency. Frequency spectrum in the range of 30 kHz - 300 kHz, corresponding to wavelength from 10 km to 1 km. A.k.a. longwave. LF band is used mainly for navigation and weather systems.

Logical Link Control. The upper sub-layer of Data Link Layer that receives and sends packets and performs error-checking.
Also see MAC and Data Link Layer.

Local Multipoint Distribution Services. A fixed, ATM-based, point-to-multipoint, broadband wireless access technology using microwave at frequency bands ranging from 27 GHz to 31 GHz.
Also see MMDS.

Local Number Portability. A system that allows a telephone user to change operator without changing telephone number.

Another name of access network. Often mentioned as the Last Mile because it refers to the last segment of telecom network between a Central Office (CO) or an access node to a subscriber home.

Line Of Sight. Refers to a condition in wireless communication where a signal travels over a direct path from the transmitter to the receiver, without obstructions in between.
Also see NLOS.

Another name for parallel port or printer port in a computer.