LE BB error LENGTH_ERROR while trying to send notifications.

RE: LE BB error LENGTH_ERROR while trying to send notifications.

ovrebekk — Mon, 31 Aug 2020 07:20:26 GMT

Please do.

The SoftDevice architecture is very mature at this point, and bugs of this nature are extremely rare, so I am pretty sure the issue will go away if you run the SoftDevice/Nordic link layer on both sides.

Also, you could check which version of the open source link layer they are currently running. There might be a more updated version on the master branch of the Zephyr repository.

Best regards
Torbjørn

RE: LE BB error LENGTH_ERROR while trying to send notifications.

JeanMBoones — Fri, 28 Aug 2020 15:03:53 GMT

I am not sure its possible to swap things over as its a testing system. I will give this to the testers. Thanks.

RE: LE BB error LENGTH_ERROR while trying to send notifications.

ovrebekk — Fri, 28 Aug 2020 08:23:18 GMT

Normally the peripheral is the advertiser and server, and the central is the scanner and client, yes. But for the sake of confusion you can have a server on the central side also (and a corresponding client in the peripheral).

Discussing this with the developers they have seen an issue before where the Zephyr open source link layer would incorrectly send a packet to the peer device at the same time the peer is sending something. This will lead to a packet collision on air, which can confuse the sniffer since it's suddenly receiving two packets at once.

Is there any chance you can try to configure the central device to use the Nordic link layer instead of the open source one, to see if the issue remains?

Best regards
Torbjørn

RE: LE BB error LENGTH_ERROR while trying to send notifications.

JeanMBoones — Thu, 27 Aug 2020 15:01:51 GMT

The peripheral (advertiser, server?) is running the S140 stack (v6.1.1). This is the device that is sending out the seemingly incorrect packets. The central (client?) is running Zephyr OS v2.0.0.

RE: LE BB error LENGTH_ERROR while trying to send notifications.

ovrebekk — Thu, 27 Aug 2020 14:54:42 GMT

Thanks for sharing the log, I have forwarded it to the stack team.

The developer looking at it was quite adamant that at least one of the devices were not running the SoftDevice stack.

Can you confirm which devices you are running on the client and server side?

Best regards
Torbjørn

RE: LE BB error LENGTH_ERROR while trying to send notifications.

JeanMBoones — Wed, 26 Aug 2020 19:33:40 GMT

The other device is a Nordic Dev board. nrf52840 SDK Board (PCA10056)

RE: LE BB error LENGTH_ERROR while trying to send notifications.

JeanMBoones — Wed, 26 Aug 2020 14:03:58 GMT

Sure, here is the sodera log. Thanks!

devzone.nordicsemi.com/.../lengtherror.zip

RE: LE BB error LENGTH_ERROR while trying to send notifications.

ovrebekk — Wed, 26 Aug 2020 12:23:40 GMT

Are you able to share the full sniffer log from the sodera sniffer, so we can take a closer look at the communication?

I assume the 'external client' is not a Nordic device, but maybe a smart phone of some kind?

Best regards
Torbjørn