nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Thu, 14 May 2020 13:36:41 GMT

All right. Perhaps for future generations this will be useful when it's implemented, if ever.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Thu, 07 May 2020 13:46:17 GMT

Reported internally as a feature request.

Just to mention, this would not be a quick fix, it would require some restructuring on the modem side etc. So this is not something that will change in the near future.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Tue, 05 May 2020 08:22:28 GMT

All right. Then we will hardcode it.

I read you have 3 simultaneous TLS sockets available at the same time in your modem implementation.

No change of setting up how many sockets I want to use, ie getting a larger TLS buffer for 1 single socket since that's all we use?

Future perhaps? Anyone you could take this to, as a request?

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Tue, 05 May 2020 08:00:15 GMT

Hi Johan,
sorry for the delay.
There is no way to read this number out.
The TLS buffer size is restricted around 2048bytes because of limited memory resources.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Tue, 05 May 2020 06:44:54 GMT

I would like a discussion on this one with Nordic. Why no contact on this?

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Fri, 24 Apr 2020 13:23:21 GMT

Thanks.

I wonder still, what function call I can make to get this number fetched - so when it changes - I dont need to update my app, instead it fetches the current max size from the driver instead.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Fri, 24 Apr 2020 13:16:01 GMT

Hi Johan,
Please check the "mfw_nrf9160_1.2.0_release_notes.txt" located inside the "mfw_nrf9160_1.2.0.zip":

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Mon, 20 Apr 2020 10:17:32 GMT

Hi Martin,

Whats the way of fetching the max size of the TLS output buffer now from latest release 1.2?

Before you mentioned the 2048 bytes limitation, and we have used that. It looks like the source code uses MBED and there is a 16384 buffer there somewhere.

/Johan

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Wed, 28 Aug 2019 13:28:30 GMT

Hi,
From our extensive investigation on the Telia LTE-M network in Sweden with the nRF9160, we have found that the issue is caused by the network side.

The RLC connection release is not happening, and after that, the new connection cannot be created. This leads to long pauses in data transfers.
We have tested against the same infrastructure that Telia uses and have not seen this in other networks.

I would recommend contacting Telia Sweden to get this solved.

Best regards,

Martin L.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Mon, 19 Aug 2019 08:22:50 GMT

Yes now using NCS v1.0.0 and mfw v1.0.0. Same performance.
I just finished creating a trace and I will send it to you over email.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Fri, 09 Aug 2019 11:00:41 GMT

Hi Fredrik,

That is indeed poor performance.

How is the network coverage in your area?

Have you tested with mqtt_simple or custom code?

Using NCS v1.0.0 and mfw v1.0.0 ?

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

nordic_red — Fri, 09 Aug 2019 06:57:25 GMT

Hi Martin!

My name is Fredrik Ellner and I am a colleague to Johan. What I understand from Johan is that the when we use the nRF9160 with LTE-M cat1 it takes everything from 20s to 1 minute to successfully transmit 2048bytes (excluding hand shake, encryption, error handling etcetera). What our project need is ONE channel with maximum speed.

We need your assistance in this, because this won't do!

BR,

Fredrik

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Mon, 01 Jul 2019 11:57:59 GMT

Hi Johan,
Please confirm that the correct mfw is on the modem side by sending the AT command: AT+CGMR

Also, please clean the application flash in case there is some garbage data on it.
'nrfjprog -e'

I would like you to test out the RC4 that was just released to see if that changes anything.

The buffer is restricted to 2048, so the new mfw that is coming should include a notification that the buffer you choose is too big if it is larger than 2048.

BR,

Martin L.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Fri, 28 Jun 2019 14:58:12 GMT

I flashed the new modem firmware you sent me via email.
I tried it with first the v0.4.0 and it worked with 2048 buffer size like before (asset_tracker example, modified for our own cloud with our own keys)

I tried with buffer size 4096 and 8192. They both seem to go into writing - via the modem without an error,
but there is no response at all from the network. SUBACK is what I'm expecting via the MQTT-drivers.
Checking the cloud, there is no data uploaded either, so still only 2048 bytes works.

Using instead v1.0.0-rc3, and the standard unmodified asset_tracker, I get

```

***** Booting Zephyr OS v1.14.99-ncs2-rc4 *****

Flash region     Domain     Per***** Hardware exception *****

Current thread ID = 0x20001870

Faulting instruction address = 0x30100

Fatal fault in ISR! Spinning...

```

Note how I'm building and uploading.
1. Building from menu, "Build Solution".
2. Menu "Target -> Connect J-Link".
3. Menu "Target-> Download file -> Download Intel Hex File -> and choosing the merged.hex

This is from how you told me earlier.

Perhaps something has changed again, so this way of flashing and running is wrong?

Johan

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Fri, 28 Jun 2019 09:18:45 GMT

Hi Johan,

I would highly recommend that you test out the newest NCS v1.0.0-rc3 to see if that changes the behavior since there have been several fixes implemented.

cd ncs/nrf
git checkout master
git pull
git checkout v1.0.0-rc3
west update

Then rebuild and try your solution.

Also make sure to have the newest modem firmware: https://www.nordicsemi.com/Products/Low-power-cellular-IoT/nRF9160/Download#infotabs

Best regards,

Martin L.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Wed, 26 Jun 2019 14:55:37 GMT

I tried this and result was:

Trial 1: sent 2 packets of 1990 bytes.
Packet 1, sent ok.
Packet 2, sent ok.
Response came in, for packet 1, then for packet 2.
OK!

--------------

Trial 2: Sent 10 packets of 1990 bytes

Packet 1, sent ok.
Packet 2, sent ok.
PAcket 3, ---> mqtt.c:client_disconnect() -> MQTT_EVT_DISCONNECT (-95)
Errno lookup gives this.

EIO

I/O error

Packet 4..10 - same failure.
Errno lookup gives this.

128

EKEYREVOKED

Key has been revoked

So there is no support for sending multiple packets in sequence, more than 2? Bug again or limitation of some kind?

I need to bring sending speed here, and optimize for transmission. Otherwise I get 300bytes/sec, by waiting for each ACK before I can send the next packet.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Johan — Wed, 26 Jun 2019 14:49:05 GMT

Ok, looking forward to that bugfix.

Will you enable us to send larger packets later? Is there a limitation somewhere? Is there power to save to send more in a bigger chunk, than to send them separately?

So, how to get up speed when needing to send a large data buffer?

I'm thinking to split the big chunk of 300KB (example size), into like you suggest, smaller parts

* send part 1

* send part 2

...

* send part n

immediately after eachother.

There is no need to wait for the ACK for each part before sending the next I'm guessing.

RE: nRF9160 send larger MQTT payloads than 2048 bytes to save battery power (need to send 200KB)

Martin Lesund — Wed, 26 Jun 2019 14:34:42 GMT

Hi Johan,

It is a bug.

The TLS output buffer has a size of 2kB, and there is a bug that you do not get a notification that the messages are too big. (this will be fixed)

So the solution is to have shorter messages.

Best Regards,

Martin L,.