This glossary includes key terms of the IoT (Internet of Things) & M2M (machine-to-machine) communications industry, including wireless and cellular technologies spanning many different markets. It is updated to present current terminology and usage. Your participation and feedback are most welcome—to submit comments, new entries, or suggestions, contact us today.

# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
There are 11 names in this directory beginning with the letter L.
L2TP
Layer 2 Tunneling Protocol. This is a tunneling protocol used to support virtual private networks (VPNs) or as part of the delivery of services by ISPs. It does not provide any encryption or confidentiality by itself, relying on an encryption protocol that it passes within the tunnel to provide privacy.
LED
Light-Emitting Diode.
Light-Emitting Diode (LED)
A semiconductor that generates light via electroluminescence. Infrared LEDs can be used for the remote control units of many consumer electronics.
Link Budget
An accounting of all of the losses in a wireless communication system. In order to “close the link,” enough RF energy has to make it from the transmitter to the receiver. (Losses include antennas, structural attenuation, propagation loss, etc.)
LLN
Low power and Lossy Networks.
Local Area Network (LAN)
A network of devices in relatively close proximity, prior to the point of transmission over leased telecommunication lines. The two most common communications technologies used in LANs are Ethernet and Wi-Fi.
Long Term Evolution (LTE) / 4G
LTE, often referred to as 4G, is the latest cellular network type, offering superior data transfer speeds than its predecessor, 3G, and it’s part of the GSM upgrade path. Portable devices can now access data at high-speed broadband speeds through LTE. Depending on where in the world you are, LTE may be implemented using different frequency bands. For example, European LTE uses 700/800/900/1800/2600 MHz bands, where North America uses 700/750/800/850/1900/1700/2100(AWS)/2500/2600 MHz.superior data transfer speeds than its predecessor, 3G, and it
Low power and Lossy Networks (LLN)
These networks are comprised of embedded devices with limited power, memory, and processing resources. LLNs are typically optimized for energy efficiency, may use IEEE 802.15.4, and can be applied to industrial monitoring, building automation, connected homes, healthcare, environmental monitoring, urban sensor networks, asset tracking, and more.
Low Power Wide Area (LPWA)
These networks are built specifically for M2M communications and offer long-range, low-power consumption. They solve cost and battery-life issues that cellular technology cannot, and LPWA networks solve range issues that technologies like Bluetooth or BLE struggle with.
Low Power Wireless Sensor Network
A group of spatially distributed, independent devices that collect data by measuring physical or environmental conditions with minimal power consumption.
LTE
Long Term Evolution.