Maximum load of downlink data

ChirpStack Application Server
#1
  • queue_item_id:“fc8cf719-d597-45ce-8a6d-5a949cf08b1d”
  • max_payload_size:“51”
  • item_size:“252”

I tried to use ENqueue to send downlink data, but an error was reported when my data size was larger than 50bytes. How can I change max_payload_size

#2

I have solved this problem, max_payload_size is related to MAC version in device profile, before I used LoRaWAN1.0.2, now I use LoRaWAN1.0.0

#3

Hi there :wave:,
The max payload size for downlinks is fixed by the spec.
So changing your DR seems to be a good start, but even with DR5, max is 222.
See: LoRa best practices Packet Optimisation Packet Size Considerations | DEVELOPER PORTAL

1 Like
#4

Thank you very much for your answer

1 Like
#5

HI
I tried to configure CN470, and I got MAC version LoRaWAN= 1.0.2A. I sent the downlink data through enqueue, but when DR=5, I was still prompted that the maximum load was 51. Why?

#6

It depends on the region, so you have to dive into the spec for CN470.

#7

NO NO NO
I actually sent 100 bytes, he didn’t report an error, and when I sent 101bytes, he told me:

    • tenantId:“52f14cd4-c6f1-4fbd-8f87-4025e1d49242”
    • tenantName:“ChirpStack”
    • applicationId:“2ba207b9-9149-4550-b74b-65f5e7ce9d2f”
    • applicationName:“test-001”
    • deviceProfileId:“2cd5488e-849c-46b6-b45f-774f4ba0627b”
    • deviceProfileName:“device profile”
    • deviceName:“txt-000”
    • devEui:“ff000000000020a6”
  • level:“ERROR”
  • code:“DOWNLINK_PAYLOAD_SIZE”
  • description:“Device queue-item discarded because it exceeds the max. payload size”
  • :arrow_forward:

context:{} 3 keys

  • max_payload_size:“51”
  • item_size:“60”
  • queue_item_id:“84bc6854-b6a9-4c69-96b5-fd4edb8818b5”