sniffer missing packets

[Vala]

Hi,

I have Wireshark version 1.10.14 and sniffer version 1.0.1. I send the data out from PCA10040 with connection interval of 7.5 ms and packet throughput of 200Hz using NUS service. I noticed that there are some packets that Wireshark do not show but I still have them received on Master point, which is an android app.

Is it normal for Sniffer to miss the packets? Is there any solution?

Vala

Edit: I added an image of Wireshark's output where this issue happens. I am sending 20 bytes packets in which the last two bytes (as a 16 bit integer) are increment in each iteration. UART packet numbers show the packet losses. Also I am sure that the Master has received the two missing packets here, which are the ones with the two last bytes of 0x530b and 0x530e.

Edit: I added a PCAP file from Wireshark. The SDK that I did this test with is v11.0.0. And the peer device is an Acer tablet running a modified version of Nordic's UART app. The only modifications to the app were some changes in presenting the data.

Sniffer Packet Loss.pcap

[run_ar]

I would say that yes, it's normal that you miss some packets using this sniffer. Remember that a commerzial sniffer use very expensive broadband radios, so you cannot really compare the performance betweent them and the nrf sniffer which is a very cheap development tool.

You can see if there are missing packets by looking at the connection event counter in the sniffer. Note that it would be easier to comment on this if you upload an example trace to your question.

[Vala]

Thanks run_ar. I added an image as you suggested.

[run_ar]

Would you mind uploading the pcap file as well? It could be interesting to see this for debugging purposes. Also, which SDK version are you using? and what is the peer device in this case? Thanks

[run_ar]

Which segger firmware are you using? For the sniffer you should downgrade to segger jlink firmware version 5.10n. ref: the troubleshooting part of this blog. The firmware can be found in the blog post.

[Vala]

Sure. I added the PCAP file. I am not sure how I can get the Segger jlink firmware version. Could you guide me through that? Can I do it by jlink commander? It gives me the following information when I connect to the dongle that is used as sniffer: Firmware: J-Link OB-SAM3U128-V2-NordicSemi

[run_ar]

See the trouble shooting section of this blog post. Go to Downgrade all your nRF5x boards to segger jlink firmware version 5.10n For instructions how to downgrade the board.