nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Hung Bui — Thu, 11 Jun 2015 10:34:31 GMT

@Zitter: We did some more investigation on the trace you sent us. The interesting part is that the CONNECT REQ was on channel 38 but there was no advertising packet on channel 38 captured right before that. The way our chip broadcasting (and scanner scanning) by default hopping from channel 37 to 38 and then 39. I suspect that the hopping sequence could be different on Broadcom chip. The sniffer didn't expect the CONNECT REQ in that case (because it hasn't received the advertising packet to perpare for the connect request) so this explain why the connection wasn't followed.

My suggestion for you is to try changing the channel hopping secquence for scanning. You can do that by pressing "h" in the scaner console. Then you can select the hopping sequence, or can select to scan for just 1 channel. Note that if you scan for 1 channel there is only 33% chance that you can catch a connection. But it worth some tries. I would suggest to try on channel 38.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Zitter — Wed, 10 Jun 2015 09:05:43 GMT

I'll do a new trace later tonight. I'll also try and do the test in another venue to see if the issue observed might be interference related.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Zitter — Wed, 10 Jun 2015 08:42:23 GMT

I've tried this with an iPad air 1. I've also tried it with an Android Galaxy 3 and an Windows Phone Lumia 930. I get the same result in all cases.

With a Nordic device, do you mean a device purchased in the Nordics or do you mean a device with a Nordic Semiconductor chip inside? :-) I suspect that the thermometer could be from the US.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Hung Bui — Wed, 10 Jun 2015 07:59:54 GMT

@Zitter: Could you let me know which iOS device did you use and the iOS version running on it ?

It's could be the issue that the peripheral is not Nordic, but it should has nothing to do with the packets from the central which is an iOS device. I'm suspecting the issue with the clock accuracy on the Iphone 6 that is not matched with the accuracy on the CONNECT REQ.

Could you upload a trace that you test with the same phone and a Nordic device ?

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Zitter — Tue, 09 Jun 2015 16:01:17 GMT

Hi Hung. I've attached the capture/trace. I'm not sure what you mean by "tried without pairing the device"?

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Hung Bui — Tue, 09 Jun 2015 12:01:22 GMT

@Zitter: Could you attach the full sniffer trace you have with the Broadcom BCM20732 chip to your question ?

it's pretty strange that the sniffer managed to catch connect request but not managed to follow it.

Have you tried without pairing with the device ?

Just want to mention here that we made and only test the sniffer for using with our BLE device, no test has been done on other vendor's chip.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Zitter — Mon, 08 Jun 2015 19:03:46 GMT

Hi Hung,

Thanks for helping out and the suggestion. I've now had the chance to try it out with Wireshark v1.10.14. The result is unfortunately exactly the same.

Regarding the chip used by the peripheral, I don't know yet which chip is used in the device as the devices is enclosed and not easily disassembled. I will try and find out.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Hung Bui — Mon, 08 Jun 2015 15:53:36 GMT

@Zitte: Do you have the problem when using with Wireshark v1.10 ? It's pretty strange that you don't have any data after they get connected. Is the BLE thermometer running on a Nordic's chip ? Or it is from other vendor ?

Our sniffer was made to sniff communication from peripheral running on our chip.

RE: nRF Sniffer intercept ADV, SCAN and CONNECT packages but no data packages

Hung Bui — Thu, 04 Jun 2015 17:30:37 GMT

@Zitte: Please use Wireshark v1.10