What's the Maximum Uplink payload in nRF9160 to the cloud?

[Jeffery]

Hi Nordic

Asking this question to Nordic AI (right-down window), below was the answer.

The nRF9160 is a cellular IoT device, and its MTU size depends on the protocol being used. For MQTT publishing, which is a common use case for IoT devices:

When not publishing in datamode, the maximum publish size is 1024 bytes.

When publishing in datamode, the maximum size is limited by the datamode ring buffer size, which is 4KB (4096 bytes).

However, it's important to note that there's a TLS secure socket buffer size limitation of 2KB (2048 bytes) according to the modem firmware release notes.

We had a new nrf91 project which required packet payload over 4KB.  And, bigger is better.

 

Q1. As AI said, MQTT TLS, max payload is 2KB.  At ncs/mqtt sample, is there any way to increase max payload?   If yes, how to do?

Q2. How about max payload for HTTPs protocol? At ncs/https sample, is there any way to increase max payload?   If yes, how to do?

Thanks

Jeff

[Michal]

Hello,

Q1. As AI said, MQTT TLS, max payload is 2KB.  At ncs/mqtt sample, is there any way to increase max payload?   If yes, how to do?

Since it's using TLS, there is no way to do that currently.

Q2. How about max payload for HTTPs protocol? At ncs/https sample, is there any way to increase max payload?   If yes, how to do?

Assuming HTTPS, you run into the same issue.

Also, remember to count the MQTT/HTTPS headers etc. as part of the payload.

Best regards,

Michal