Packet Forwarder vs. Built-in LNS: Choosing the Right LoRaWAN Gateway Mode

You've unboxed your new LoRaWAN gateway, powered it on, and it's ready to connect. But connect to what, and how? This is a fundamental question that I've seen trip up many developers. The way your gateway handles data packets determines your network's latency, reliability, security, and cost. It's a strategic decision that goes far beyond a simple configuration toggle.

At its core, every LoRaWAN packet needs to get from your sensor, through the gateway, to a LoRaWAN Network Server (LNS), which is the brain of the network. The choice of LoRaWAN gateway mode dictates where that brain lives. Does it live in the cloud, or can it live directly inside your gateway? This distinction is a core concept for any  Industrial IoT Edge Gateway  , and understanding the trade-offs is key to building a successful LoRaWAN solution.

Packet Forwarder mode is the most traditional and common of the LoRaWAN gateway modes .

In this mode, the gateway acts as a simple and dumb "bridge." Its only job is to receive all raw LoRaWAN radio packets from the air and immediately forward them, usually over a standard IP connection (Ethernet, Wi-Fi, or Cellular), to a separate, external Network Server. This LNS can be a public service like  The Things Network , a commercial platform like LoRiot, or a self-hosted ChirpStack instance running in the cloud or a data center.

• Simple Gateway Configuration: Setting up the gateway itself is incredibly easy. You typically only need to point it to the IP address of your Network Server.

• Centralized Management: If you have dozens of gateways spread across a large area, having them all point to a single, centralized LNS in the cloud can simplify management.

• Easy to Connect to Public Networks: This is the required mode for connecting your gateway to public or community-run LoRaWAN networks.

• Requires Constant Internet Connection: Let's be clear: if the gateway's internet backhaul fails, it becomes a paperweight. It cannot receive or buffer messages, and your entire network segment goes down.

• Higher Latency: The round-trip time for a packet to travel from the gateway to the cloud LNS and for a command to travel back can introduce significant latency, making it unsuitable for real-time control applications.

• Data Sovereignty & Security Concerns: Your raw data passes through the public internet and (in the case of public networks) third-party servers, which may not be acceptable for sensitive industrial or corporate data.

• Higher Data Costs: All LoRaWAN traffic, including metadata and keep-alives, is sent over your internet backhaul, which can increase cellular data costs.

With the rise of more powerful hardware, a new, more robust LoRaWAN gateway mode has become popular: running the Network Server directly on the gateway.

In this mode, the LoRaWAN gateway is the Network Server. It receives LoRaWAN packets, processes them, de-duplicates them, and handles all the LoRaWAN MAC layer logic right on the device. It then forwards the decrypted application data directly to your application server, often via a lightweight MQTT message. This is a true edge computing architecture.

• Full Data Sovereignty and Security: Your data can be processed entirely on your local network without ever touching the public internet, providing maximum security.

• Ultra-Low Latency: Since the Network Server is on the same device as the radio, downlink commands and acknowledgments are nearly instantaneous.

• Offline Operation: This is the killer feature. If the gateway's internet backhaul fails, the LoRaWAN network continues to function perfectly. The gateway can keep receiving data, controlling local devices, and buffering data until the internet connection is restored.

• Reduced Data Costs: Only clean, decrypted application data is sent over the internet backhaul, significantly reducing cellular data usage.

• Requires a More Powerful Gateway: You need a gateway with sufficient CPU, RAM, and storage to run the LNS software, such as ChirpStack, in addition to its packet forwarding duties.

• More Initial Setup: The initial configuration of the LNS on the gateway is more involved than simply pointing a packet forwarder at an IP address.

• Decentralized Management: If you have many gateways, each running its own LNS, you need a strategy to manage them (though this can be done via a cloud platform like RCMS).

Feature	Packet Forwarder Mode	Built-in LNS Mode
Setup Complexity	Very Simple	More Involved
Data Path	Gateway -> Internet -> Cloud LNS	Gateway -> (Optional) Internet
Latency	High (100s of ms to seconds)	Very Low (milliseconds)
Offline Capability	None	Full Local Operation
Data Sovereignty	Lower (data crosses internet/3rd parties)	Complete
Best For	Public Networks, Non-Critical Apps	Private Networks, Industrial Control

So, how do you decide? It comes down to your application's requirements.

• Choose Packet Forwarder Mode if:

  • You are connecting to a public or existing third-party LoRaWAN network.

  • You have many gateways and want to manage a single LNS instance in the cloud.

  • Your application is not time-sensitive and can tolerate internet latency.

• Choose Built-in LNS Mode if:

  • You are building a  Private LoRaWAN Network  for a specific site (like a farm, factory, or building).

  • You require high reliability and offline operation .

  • Your application requires ultra-low latency for control or command responses.

  • Data sovereignty and security are your top priorities.

Choosing a versatile gateway is key. An industrial gateway like the  Robustel R1520LG  is powerful enough to run a full ChirpStack LNS locally, making it a perfect all-in-one solution for a private network. At the same time, it can be easily configured to operate as a simple, reliable packet forwarder for connecting to any external network server. This flexibility allows you to adapt your strategy as your needs evolve.

The choice between LoRaWAN gateway modes is a foundational decision in your IoT network design. While Packet Forwarder mode offers simplicity and easy access to public networks, the Built-in LNS mode provides the security, reliability, and performance demanded by serious industrial and commercial applications. By understanding the trade-offs and selecting a flexible, industrial-grade gateway, you can build a LoRaWAN solution that is perfectly tailored to your project's unique requirements.