This page presents three simple examples to explain how LoRaWAN downlink reception works depending on network latency and responsiveness.

The device always opens two reception windows after each uplink:

• RX1 – opens shortly after sending
• RX2 – opens later, giving the network more time

If the network is slow or unstable, the response may arrive too late for RX1 and only RX2 will be usable.

Key Points:

• Low latency (100–300 ms)
• Server close to gateways
• Downlink ready quickly

Result:

• RX1 = OK ✔️
• RX2 is not needed

Key Points:

• Cloud-hosted server (AWS / Azure)
• Gateway in 4G
• Latency fluctuates (800 ms to 1.5 s)

Result:

• RX1 = Borderline ⚠️
• Sometimes RX1 works, sometimes the response arrives too late
• RX2 used as fallback ✔️

Recommendation: Increase RX1Delay (ex: 1 → 3 seconds)

Key Points:

• Weak cellular or satellite links
• High backend processing load
• Latency above 2–3 seconds

Result:

• RX1 = FAIL ❌
• RX2 = Only reliable option ✔️

• RX1 requires the network to respond quickly.
• RX2 provides a safety margin when the network is slow.
• Increasing RX1Delay helps but cannot fix very slow networks.