Wireless Glossary – L

Level 2 Tunneling Protocol over IP Security. One of several virtual private network (VPN) implementation schemes. Regardless of whether Subscriber Modules have the Network Address Translation feature (NAT) enabled, they support VPNs that are based on this protocol.

A Local Area Network (LAN) is a network of limited size to which computers and devices can connect so that they can communicate with each other.

Light Amplification by Stimulated Emission of Radiation. An electro-optic device that produces coherent light with a narrow range of wavelengths, typically centered around 850 nm, 1310 nm, or 1550 nm. Lasers with wavelengths centered around 850 nm are commonly referred to as VCSEL.

The telecommunications technology that connects the customer’s home directly to the Internet or telephone provider.

This field displays how many late collisions occurred on the Ethernet controller. A normal collision occurs during the first 512 bits of the frame transmission. A collision that occurs after the first 512 bits is considered a late collision. A late collision is a serious network problem because the frame being transmitted is discarded. A late collision is most commonly caused by a mismatch between duplex configurations at the ends of a link segment.

Acceptable tolerance for delay in the transfer of data to and from a module.

Cable in which the fiber buffer tubes (transmission elements) are arranged in layers around a central member (see central member).

This sublayer protocal of PPP is in charge of negotiating authentication, multilink, compression, and callback.

Low-Density Parity Check code is a linear error correcting code, a method of transmitting a message over a noisy transmission channel, and is constructed using a sparse bipartite graph.

A WAN point-to-point, dedicated connection between two locations. It is typically the most expensive WAN connection type.

Length Indicator is a field in the Radio Link Control header, showing the length in bytes of a corresponding Data field element in a RLC data Protocol Data Unit.

A license file is used to enable certain features of the unit. The unit already has a license file when it is shipped. When more features become available, you can purchase a license file and download it to the unit to enable these additional features.

A light-emitting diode (LED) is a semiconductor device that emits incoherent narrow-spectrum light when electrically biased in the forward direction. This effect is a form of electroluminescence. The color of the emitted light depends on the chemical composition of the semiconducting material used, and can be near-ultraviolet, visible or infrared. Nick Holonyak Jr. (born 1928) of the General Electric Company developed the first practical visible-spectrum LED in 1962.

An unobstructed straight line between two transmitting devices. Line of sight is typically required for long-range directional radio transmission. Due to the curvature of the earth, the line of sight for devices not mounted on towers is limited to 16 miles (26km).

An IPv6 address type that is auomatically generated when an IPv6 node goes online and is automatically assigned. These addresses can only go as far as the Layer 2 domain.

Faster to converge than distance vector routing protocols, the link-state routing protocols are a class of routing protocols in which all possible link statuses are stored in an independent topology table. In this independent topology table, the best routes are calculated and put into the routing table. The topology table is initially synchronized with found neighbors followed by frequent hello messages.

Line Impedance Stabilization Network is a device to create a known impedance on power lines of electrical equipment during electromagnetic interference testing. A LISN is typically designed to allow for measurements of the electromagnetic interference existing on the power line.

No user data is sent in this STP port state. The interface transitions to a forwarding state by listening and sending BPDUs.

Logical Link Control data communication protocol layer is the upper sublayer of the data link layer, which is itself layer 2.

According to the IEEE 802 family of standards, Logical Link Control (LLC) is the upper sublayer of the OSI data link layer. The LLC is the same for the various physical media (such as Ethernet, token ring, WLAN). The LLC sublayer is primarily concerned with: multiplexing protocols transmitted over the MAC layer (when transmitting) and demultiplexing them (when receiving) optionally providing flow control, and detection and retransmission of dropped packets, if requested

Frame Relay service providers and customer premises equipment use this signaling method to communicate.

Least Mean Squares algorithms are a class of adaptive filter used to mimic a desired filter by finding the filter coefficients that relate to producing the least mean squares of the error signal (difference between the desired and the actual signal). It is a stochastic gradient descent method in that the filter is only adapted based on the error at the current time.

Furthest left LED in the module. In the operating mode, this LED is continuously lit when the Ethernet link is present. In the aiming mode for a Subscriber Module or a Backhaul timing slave, this LED is part of a bar graph that indicates the quality of the RF link.

A part of the antenna radiation pattern between adjacent minima.

The maximum physical speed a WAN connection is able to attain.

Final octet of the 4-octet IP address of the module.

A test signal sent to a network destination that is returned as received to the originator. The returned signal may help diagnose a problem.

Several fibers in a common loose buffer tube.

Line-Of-Sight is a type of propagation that refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line. The rays or waves may be diffracted, refracted, reflected, or absorbed by atmosphere and obstructions with material and generally cannot travel over the horizon or behind obstacles.

Location Registration is for the user equipment that registers its presence in a registration area, regularly or when entering a new registration area.

This Ethernet specification developed by Cisco can reach a maximum segment length of 5000m, providing broadband service over existing telephone-grade or Category 1, 2, or 3 wires with speeds varying between 5 to 15Mbps.

Localised Service Area is an operator-defined group of cells, for which certain access conditions apply.

These are used to send hello messages, metrics used, and other variables on attached interfaces. Utilized by OSPF.

Long Term Evolution, marketed as 4G LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using a different radio interface together with core network improvements. The standard is developed by the 3GPP (3rd Generation Partnership Project) and is specified in its Release 8 document series, with minor enhancements described in Release 9.

4M Wireless 3GPP Release 8 compliant completion of the LTE protocol stack for User Equipment (UE) terminals.