Glossary of Mesh Networking Terms

A reference for terminology used throughout this wiki and in the mesh networking community.

A

Advertisement (advert): A packet broadcast by a MeshCore node to announce its existence on the network. Advertisements contain the node's identity, position (if configured), and routing credentials. Other nodes use advertisements to discover repeaters and build routing tables.
APRS (Automatic Packet Reporting System): An amateur radio protocol for broadcasting GPS positions and short messages. Some mesh gateways bridge position data to the APRS network, making mesh nodes visible on aprs.fi.
Autonomy period: How many days a battery-powered node can operate without solar input or recharging. A standard design target for solar-powered repeaters is 5 days of autonomy.

B

Bandwidth (BW): In LoRa, the width of the frequency channel used for transmission. Wider bandwidth = faster data rate but less range. Common values: 62.5, 125, 250, 500 kHz. The MeshCore USA/Canada preset uses 62.5 kHz BW.
BLE (Bluetooth Low Energy): The wireless connection method used by most LoRa mesh apps to communicate with companion devices. BLE has a typical range of ~~30–~~30 - 100 feet and consumes very little power.

C

CAD (Channel Activity Detection): A LoRa radio feature that listens for activity on the channel before transmitting, reducing collisions. Also called listen-before-talk (LBT).
Channel: A logical grouping of nodes that can communicate with each other. Nodes must be on the same channel to exchange messages. Channels can be public (no PSK) or private (encrypted with a shared PSK). Both MeshCore and Meshtastic support multiple channels.
Coding Rate (CR): A LoRa parameter that controls forward error correction overhead. Higher CR (e.g., 4/8) adds more redundancy, allowing the receiver to reconstruct damaged packets. Lower CR (4/5) has less overhead but requires cleaner signals. Affects airtime and link budget.
CascadiaMesh: A MeshCore community mesh network covering the Pacific Northwest (Oregon, Washington, and into British Columbia). Operates a backbone infrastructure along the I-5 corridor. See cascadiamesh.org.

D

dBi (decibels relative to isotropic): A measure of antenna gain relative to a theoretical perfect omnidirectional antenna. A 6 dBi antenna radiates 4× more power in its main direction compared to an isotropic antenna. Higher dBi = more directional (for verticals: more concentrated horizontally).
dBm (decibels relative to milliwatt): A measure of power level. 0 dBm = 1 mW. 27 dBm ≈ 500 mW. 30 dBm = 1000 mW = 1W. Used to express transmit power and signal strength (RSSI).
DFU (Device Firmware Update): A firmware update mode on nRF52840-based devices (T-Echo, RAK4631, etc.). Entered by double-tapping the reset button. The device appears as a USB drive, and firmware is updated by copying a .uf2 file to it.

E

EIRP (Effective Isotropic Radiated Power): The total RF power broadcast in the main direction of the antenna, accounting for both transmit power and antenna gain. FCC Part 15 limits US ISM band equipment to 4W (36 dBm) EIRP. With a 6 dBi antenna at 30 dBm TX, EIRP = 36 dBm —- at the legal limit.
EasySkyMesh: A community fork of MeshCore firmware optimized for ultra-low power consumption, targeting the Heltec V4.3 platform. Achieves ~5.5 mA average idle current. Not the official MeshCore firmware.

F

Flooding: A routing approach used by Meshtastic where every received packet is re-broadcast by every router node (up to the hop limit). Simple and robust but creates significant traffic in dense networks. Contrast with path-discovery routing (MeshCore).
Firmware: The software that runs on a LoRa device. Determines which protocol (MeshCore or Meshtastic), which features are active, and how the radio is configured. Flashed to the device via USB using a web flasher or PlatformIO.

G –- H

Gateway: A node that bridges the mesh network to the internet. In Meshtastic, gateways typically use MQTT. In MeshCore, gateways are usually implemented via room servers with internet uplinks.
HAL (Hardware Abstraction Layer): A software layer in MeshCore firmware that separates platform-specific hardware code (ESP32, nRF52840) from the common protocol logic. Allows the same firmware core to run on different MCU families.
Hop: One relay of a message from one node to the next. A message with 3 hops has been relayed through 3 intermediate nodes between sender and receiver. Each hop adds latency and reduces reliability. Most deployments target 3–3 - 5 hop maximum.
Hop limit: The maximum number of times a packet is relayed before being discarded. Prevents packets from circulating indefinitely in the mesh.

I –- L

ISM band: Industrial, Scientific, and Medical frequency bands designated for unlicensed use. In North America, the ~~902–~~902 - 928 MHz band (commonly called "915 MHz") is used for LoRa mesh. In Europe, ~~863–~~863 - 870 MHz ("868 MHz").
LiFePO4 (Lithium Iron Phosphate): A rechargeable battery chemistry preferred for outdoor mesh deployments. Advantages over LiPo: wider temperature range, longer cycle life (2000+ vs ~~300–~~300 - 500 cycles), safer (will not catch fire), lower energy density. Nominal voltage: 3.2V per cell.
Link budget: The total signal loss a radio link can absorb while still achieving reliable communication. Calculated as TX power + antenna gains − required receive sensitivity. Higher link budget = more range or better penetration through obstacles. A larger spreading factor increases the link budget (but reduces data rate).
LoRa (Long Range): A proprietary chirp spread-spectrum radio modulation developed by Semtech. LoRa achieves exceptional range at low power and low data rates. The physical layer technology underlying both MeshCore and Meshtastic.
LoRaWAN: A network protocol that uses LoRa radio. Different from LoRa mesh —- LoRaWAN requires centralized gateways and a network server. MeshCore and Meshtastic are not LoRaWAN.

M –- N

MCU (Microcontroller Unit): The processor chip in a LoRa node. Common MCUs: ESP32-S3 (higher power, has Wi-Fi), nRF52840 (ultra-low power, BLE only). Choice of MCU significantly affects power consumption and available interfaces.
MeshCore: A free, open-source LoRa mesh networking protocol and firmware. Uses path-discovery routing and AES-256-CTR encryption. Strong North American community with several regional networks. Not to be confused with Meshtastic.
Meshtastic: A free, open-source LoRa mesh networking protocol and firmware. Uses flooding-based routing. Larger global community. Not interoperable with MeshCore.
MPPT (Maximum Power Point Tracking): A solar charge controller algorithm that continuously adjusts the operating point to extract maximum power from a solar panel. Recommended for all solar-powered mesh deployments. More efficient than PWM controllers, especially on small systems.
MQTT (Message Queuing Telemetry Transport): A lightweight publish/subscribe messaging protocol. Used by Meshtastic gateways to bridge mesh traffic to the internet. Some MeshCore room servers also support MQTT bridging for monitoring and integration.
NoDakMesh: A MeshCore community mesh network covering North Dakota and the Northern Plains. One of the regional networks using the standard USA/Canada MeshCore preset. See nodakmesh.org.

P –- R

Path-discovery routing: The routing approach used by MeshCore. When a node wants to reach a destination, it broadcasts a route request (~~RREQ)~~path discovery packet). Repeaters append themselves to build a route record. The destination responds with a route reply (~~RREP)~~path acknowledgment). Subsequent traffic follows the discovered path rather than flooding. More efficient than flooding in large or busy networks.
Preset: A named set of radio parameters (spreading factor, bandwidth, coding rate) that determines the tradeoff between range and data rate. Meshtastic has 9 presets (Short Turbo through Long Slow). MeshCore uses regional presets (USA/Canada, Europe, etc.). Nodes must use the same preset to communicate.
PSK (Pre-Shared Key): A shared secret key used to encrypt messages on a private channel. All nodes on the channel must have the same PSK configured. Meshtastic uses PSK per channel; MeshCore uses AES-~~256-CTR~~128 ECB with HMAC-SHA256 with separate key management.
RegionMesh: A MeshCore community mesh network covering the central United States, including Dallas-Fort Worth, Denver, Chicago, and surrounding regions. See regionmesh.com.
Room server: A MeshCore infrastructure component that runs on a server (Raspberry Pi, VPS, etc.) and provides message persistence, node discovery, and optionally internet bridging. The MeshCore equivalent of a Meshtastic MQTT gateway, but with more features.
RSSI (Received Signal Strength Indicator): The power level of a received radio signal, measured in dBm. More negative = weaker. Typical useful range for LoRa: −60 dBm (strong) to −125 dBm (minimum reliable). SNR is more informative than RSSI alone for assessing link quality.

S –- Z

SNR (Signal-to-Noise Ratio): The ratio of signal strength to background noise, measured in dB. Unlike RSSI, SNR indicates how far above the noise floor the signal is. LoRa can decode signals with negative SNR (below the noise floor) —- typically down to −7.5 to −20 dB depending on spreading factor. SNR is a better indicator of link quality than RSSI for LoRa links.
Spreading Factor (SF): A LoRa parameter (SF7 to SF12) that controls how long each symbol is transmitted. Higher SF = longer range, longer airtime, lower data rate. SF12 has ~4× more range than SF7 but is 64× slower and uses 64× more airtime per bit.
SWR (Standing Wave Ratio): A measure of impedance mismatch between a transmitter and antenna. Perfect match = 1:1 SWR. <1.5:1 is excellent for LoRa; >3:1 indicates a significant problem (damaged connector, wrong frequency antenna, etc.).
WCMesh (West Coast Mesh): A MeshCore community mesh network covering the US West Coast, with a strong presence in Oregon, Washington, and northern California. Uses the USA/Canada preset (with some regional frequency variations). See wcmesh.com.