Openthread sleepy Child re-attach process

[Edward_Atam]

Hello,

I'm using NRF52840 module to make a customer device. I'm using nRF5 SDK for Thread and Zigbee v3.0.0.

I have a Thread mesh with some routers devices and one child, Periodically, the child leave the mesh when it goes out of range of any node in the network. I would like to know how to improve the current consume.

If I plot the current consume versus time (see attached figure), I can see serveral re-attach processes. The first retries are very close in time, and then the interval increases as 2^n, (n is the try number). Also, I can see that the duration timeout of each try is about 2 seconds.. Is this correct?

I would like to know if this timeout and interval period can be set or modified. 

I have taken a screen shoot with nrf Connect Power Profile, In this picture I have observed that the check timeout(T1, green arrow) is 2 seconds and the time between retries(T2, blues arrows) is 2^n seconds (n is the number of times when the child can't attach).

Can I set this periods?

Any help is wellcome. Thank you in advance.

[AndreasF]

Hi.

First:

It is against the specification changing the RX window time for the Parent Response. If you do this you might not get your device certified. You can do it for experimental reasons if you like by chaning two variables:

ttps://github.com/openthread/openthread/blob/master/src/core/thread/mle_constants.hpp#L69
https://github.com/openthread/openthread/blob/master/src/core/thread/mle_constants.hpp#L70

Second:

This can be changed as you like by modifying OPENTHREAD_CONFIG_ENABLE_ATTACH_BACKOFF, just remember to enable it. Modifying this should not be against the spec.

Best regards,

Andreas

[Edward_Atam]

Thank you for your reply.

My devices will not connecto to any third party Thread devices. Having this in mind, I guess that reducing the RX-window time to about 1 second will not have any influence in the certification. Do you think this make sense? Also, do you think that reducing this window will highly decrease the performance of the devices?

Also, I would like to ask about how to rebuild the OpenThread project:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.thread_zigbee.v2.0.0%2Fthread_intro.html&cp=4_2_0_1_0_5&anchor=thread_qsg_libraries

It is for SDK 2.0 and I assume it doesn't work for SDK 3.0 because there are not scripts .bat in the folder /openthread/project/

Is there any guide for this SDK? Can you help me?

[AndreasF]

Hi.

Which commit did you build the libraries with?

Did you use this:

github.com/.../2279ef610eef80597bd789611d6931b95e08bf48

If you try to use master you might have problems compiling since the SDK is built upon the commit above, not on the master branch.

Best regards,

Andreas

[Edward_Atam]

Hi,

I cloned the last commit, I did today.

what commit I have to download? Have I to clone a older commit?

Did I follow the right steps? I don't know if iI have to clean some folder before to rebuild.

thanks

[AndreasF]

Hi again.

Sorry for the late reply.

Yes, you have to clone that specific commit i posted in my last reply.

You see, OpenThread is an open-source implementation of the Thread Protocol, that means that anyone can propose modifications to the implementation. So, we release the SDK with a stable commit and a precompiled library that we test thoroughly.

If you try to build your own library with another commit you have a very high chance of getting into trouble.

Best regards,

Andreas

[Edward_Atam]

Thank you very much for the information

I will try to build this commit and I will post my the result!

[Edward_Atam]

Thank you for your replies!!!

I rebuilt the number of commit that you told me and worked well.

Best regards.