Data loss while sending large data by notifications

RE: Data loss while sending large data by notifications

Bayram ZAYET — Mon, 04 Sep 2017 07:12:51 GMT

OK,

Thank you

RE: Data loss while sending large data by notifications

run_ar — Thu, 31 Aug 2017 09:39:06 GMT

Excellent, thanks. I see that Petter is already looking at that. So I'll leave it with him.

RE: Data loss while sending large data by notifications

Bayram ZAYET — Mon, 28 Aug 2017 12:37:25 GMT

here is the question and details about the problem:

devzone.nordicsemi.com/.../

RE: Data loss while sending large data by notifications

Bayram ZAYET — Mon, 28 Aug 2017 09:22:13 GMT

Hello run_ar, I would post a question but I get always a server problem when I post a question and donnow why!!

RE: Data loss while sending large data by notifications

run_ar — Mon, 28 Aug 2017 09:09:14 GMT

Bayram, Could you consider creating a new question for this. Please provide exact detail on application, SDK and SD versions. Make sure you check the error codes returned by sd_ble_gatts_hvx and describe how you handle them. It would also be interesting to know which peer device you are testing against. Thanks.

RE: Data loss while sending large data by notifications

Bayram ZAYET — Fri, 25 Aug 2017 09:43:21 GMT

Hello, Same problem here with S130 SDK12!

RE: Data loss while sending large data by notifications

FormerMember — Wed, 07 Dec 2016 11:45:36 GMT

No, the problem is not related to the SDK version, it should work fine to use SDK 11.

RE: Data loss while sending large data by notifications

Richa — Wed, 07 Dec 2016 06:05:17 GMT

is it because, I am using SDK11??

RE: Data loss while sending large data by notifications

Richa — Wed, 07 Dec 2016 06:04:18 GMT

I used the same logic of DATA_SEND_IRQn as it is in k_uart app in my peripheral application and i captured the packets received by the central, central is still not receiving all the packets

RE: Data loss while sending large data by notifications

Richa — Tue, 06 Dec 2016 12:24:08 GMT

I verified with uploaded application, there is no data loss, I have kept const buffer in k_uart app that i want to transmit, and increased the index of buffer by 20 after receiving NRF_SUCCESS, nrf-connect is receiving all the data successfully

RE: Data loss while sending large data by notifications

FormerMember — Tue, 06 Dec 2016 07:38:15 GMT

The notifications in log1.pcap are the notifications transmitted by the peripheral. Could you use the example I uploaded to check if data will be lost with that example as well, or if that example is working fine?

RE: Data loss while sending large data by notifications

Richa — Tue, 06 Dec 2016 06:01:35 GMT

I verified with the data that peripheral is transmitting, all data are transmitted, i verified it by printing the data on console that are transmitted successfully But if we see log1.pcap on central that number of received notifications are less so notifications are missing in between

RE: Data loss while sending large data by notifications

FormerMember — Mon, 05 Dec 2016 13:45:08 GMT

Where in log1.pcap is data is not correctly received?

If you go through the data that the peripheral is supposed to transmit, and the data captured by the sniffer, is the data consistent? Is there some data missing in the transmitted data?

RE: Data loss while sending large data by notifications

Richa — Mon, 05 Dec 2016 12:53:25 GMT

pcap file I attached shows that data are not received completely, and I also used nrf logger app to check the loss of data on the central side. According to nrf logger only 61k data is received, other data are loss and even it shows in pcap I attached that large amount of data is loss in between

I validated the last bytes of the buffer, last bytes of the buffer is received but data is loss in between

RE: Data loss while sending large data by notifications

FormerMember — Mon, 05 Dec 2016 12:44:25 GMT

How do you verify that the data was correctly received?

RE: Data loss while sending large data by notifications

Richa — Mon, 05 Dec 2016 12:31:32 GMT

I am using nrf connect app as a central device

RE: Data loss while sending large data by notifications

FormerMember — Mon, 05 Dec 2016 12:29:29 GMT

Okay, I see. In BLE all packets are ack'ed in the link layer. It means that if a notification is transmitted but there is no ack, that notification will be re-transmitted until ack or until connection supervision timeout (disconnect).

Which central device do you use? Is it possible that there could be some kind of data overflow on the central side?

RE: Data loss while sending large data by notifications

Richa — Mon, 05 Dec 2016 09:56:23 GMT

There is data loss, On peripheral, I have taken care of handling error codes like BLE_ERROR_NO_TX_PACKETS and NRF_SUCCESS to continue sending notification in a while loop And for any other error code other than NRF_SUCCESS or BLE_ERROR_NO_TX_PACKETS, Application stops sending notification. next notification is send only when NRF_SUCCESS is received. And I have checked on peripheral side, that it is successfully sending all the notifications but all are not received on central side. I have also attached log1.pcap in the question

RE: Data loss while sending large data by notifications

FormerMember — Mon, 05 Dec 2016 09:44:37 GMT

What do you mean by notifications are missing? Is some data lost, or is the transfer slower than expected? This blog post contains the number of packets per connection interval that various phones can handle.

How do you handle the other error codes that can be returned from sd_ble_gatts_hvx(..)? The error codes NRF_ERROR_INVALID_STATE and NRF_ERROR_BUSY do also indicate that the system is busy or the system is currently in an invalid state.

Update 06.12.2016: Could you use ble_app_uart_test_throughput.zip (SDK 12) to check if any data is lost with that example?