Unmarshal phypayload error: lorawan: 18 bytes of data are expected

1

Hello,

we are receiving lot of this error messages in loraserver log, obviusly with different data_base64:

*** *** loraserver[11332]: time="***" level=info msg=“gateway/mqtt: uplink frame received”
*** *** loraserver[11332]: time="***" level=error msg=“processing uplink frame error” data_base64=BFvlBDELAv4B error=“unmarshal phypayload error: lorawan: 18 bytes of data are expected”

These are the Loraserver packets installed:

ii lora-app-server 3.3.0 amd64 LoRa App Server
ii lora-gateway-bridge 3.2.1 amd64 LoRa Gateway Bridge
ii loraserver 3.2.1 amd64 LoRa Server

Do you have any ideas about the problem?

Thanks, regards

Gianluca

2

Are you sure this is a valid LoRaWAN payload?

3

Dear Brocaar,

thanks for your answer. I don’t know the source of the message. I only know that it come from a Multitech Lora Gateway in lora forwarder mode connected to your software.

Example of Multitech Lora Packet forwarder log:

JSON up: {“rxpk”:[{“tmst”:3101217003,“time”:“2020-01-31T11:16:47.416211Z”,“tmms”:1264504625415,“chan”:0,“rfch”:0,“freq”:868.100000,“stat”:1,“modu”:“LORA”,“datr”:“SF7BW125”,“codr”:“4/5”,“lsnr”:-5.2,“rssi”:-116,“size”:9,“data”:“BCt7BDENAv4B”}]}

I’m continuosly receiving these specific payloads that return the same error of Unmarhal…:

data_base64=BCt7BDENAv4B
data_base64=BCtxBDENAv4B
data_base64=BCtzBDENAv4B
data_base64=BCW7BDENAv4B
data_base64=BCW9BDENAv4B
data_base64=BCXDBDENAv4B
data_base64=BCZKBDENAv4B
data_base64=BJunBDENAv4B
data_base64=BJuqBDENAv4B
data_base64=BJvBBDENAv4B

Do you have any ideas about?

Many thanks,

Gianluca

4

LoRaWAN operates in an unlicensed spectrum, which means that there might be devices around you using LoRa (not LoRaWAN) of which you are receiving the payloads. In this case the NS will fail to decode these frames. If this is the case then there is nothing to worry about.

1 Like
5

Hello Brocaar,

i understand, many thanks for your explanation.

6

Dear Brocaar,

sorry for the late request about this thread. In a log like this:

mag 27 19:44:15 **** chirpstack-network-server[18736]: time=“2020-05-27T19:44:15+02:00” level=error msg=“uplink: processing uplink frame error” ctx_id=fe14086e-5f41-46e1-9749-bc3d6d75691a error=“unmarshal phypayload error: lorawan: 18 bytes of data are expected”

or in a log like this:

mag 28 11:33:29 chirpstack-network-server[18736]: time=“2020-05-28T11:33:29+02:00” level=error msg=“uplink: processing uplink frame error” ctx_id=264f941b-9c34-4732-aa80-4da5efd4bf39 error=“get device-session error: frame-counter did not increment”

how can i identify the gateway (in a multi gateway environment) or the device that the message come from?

And in general, is there a way to associate a log id (ctx_id) to specific gateways or devices if gweui or deveui is not present?

Many thanks,

Gianluca