Maximum value to be input to otLinkSetPollPeriod function as parameter

[Abhijith.Desai]

Hi,

Using windows 10 OS, and SES v5.40.

I am using nRF52833 device in my project along with nRF5_SDK_for_Thread_and Zigbee_v4.1.0_32ce5f8 SDK.

I am using openthread protocol and specifically otError otLinkSetPollPeriod( otInstance *aInstance, uint32_t aPollPeriod ) function to input the poll period.
Problem statement : the above said function is nothing but the communication poll period and i see from the documentation(https://openthread.io/reference/group/api-link-link) that it is a U32 variable which has max limit of 0x3FFFFFFF and min 10ms for its operation.
But if i run a test by inputting aPollPeriod to some higher value i can see that the value is somehow cutting down to 188s(approx. 3mins).
Ex : Test 1 : if i run with 60 sec(60000) as input i can see that the value of poll period is 60s(59999ms).
Ex : Test 2 : if i run with 200 sec(200000) as input i can see that the value of poll period is 188s(188676ms).
Ex : Test 2 : if i run with 350 sec(350000) as input i can see that the value of poll period is 188s(188676ms).

I am trying to test this with a inbuilt feature of our code that can measure the time and i have attached the debug information for further reference.

Questions:
1. what is the max value that can be input to this aPollPeriod (practically)?
2. Is 188s is the threshold for the pollperiod? 

Regards
Abhijith Desai

[Abhijith.Desai]

Hi,

Thanks for your reply on this..

Even i dont see any limitations listed in the documentation related to poll value.

I tried to do the above tests with RF wakeup (printed as wakeup in eosm) and device wakeupp (Printed as wakeup in CSA) and along with that i ran sniffer where i could see that when ever i see the RF wakeup printed at the same time i see some packets getting exchanged(the one in white lines in sniffer window) 

From that it is clear that, the poll period itsef is set to 188s even if it is set to 200 or any value above that.

Is there anyway we could see what is the exact poll period that is set inside the OT stack with some sort of library return function.

Best Regards

Abhijith Desai

[Jørgen Holmefjord]

What is the value of your child timeout? 

I tested the CLI example, and I'm not able to set the poll period above 236000 ms with the default child timeout (240s). If I increase the child timeout, I can set longer poll periods.

This makes sense, as the child would time out before polling the parent on every wakeup.