[nrf52840 + zigbee] How to handle aging timeout feature ?

[embedholic]

Hi,

I am under long run test between coordinator and end device.

End device sends a message and goes into system off state until next event(door open) for minimal power consumption.

After long period(in my case 10 hours)  in system off state of end device, if i give event to end device, end device wakes up from system off state and

 joins to the network and sends message successfully. In such case i can see several Leave messages from coordinator to end device with wireshark.

I have found that it is aging features of zigbee 3.0.

Aging time is set to 64 mins (same as light bulb example).

Question is 

1) Can i disable  aging function ? 

2) Can i make aging time to eternal ?( maximum can be found as 16384 minutes(almost 11 days))  --  ED_AGING_TIMEOUT_16384MIN /*!< 16384 minutes */

3) End device with system off state, how can make coordinator not to aging out the device ?

4) Currently end device ignores the leave message and seems it work normally. No problem with ignoring leave message ?

Thanks.

[AndreasF]

Hi again.

1) Can i disable  aging function ? 

 No, it's not allowed to disable the aging function according to the specification for Zigbee.

Zigbee Spec 3.6.10.1 End Device Aging Mechanism - "A router parent must age neighbor table entries for end devices"

2) Can i make aging time to eternal ?( maximum can be found as 16384 minutes(almost 11 days))  --  ED_AGING_TIMEOUT_16384MIN /*!< 16384 minutes */

 No, you cannot make the aging time eternal according to the specification for Zigbee.

Zigbee Spec 3.4.11.3.1 Requested Timeout Field - values are predefined, 16384 minutes are the longest period.

3) End device with system off state, how can make coordinator not to aging out the device ?

 Same answer as in question 1.

4) Currently end device ignores the leave message and seems it work normally. No problem with ignoring leave message ?

 As far as I can read from the spec it does not say anything about ignoring the leave message.

How does you device work, is it powered all the time?

Is the device a sleepy or a non-sleepy device?

Could you share a traffic dump of the case?

Best regards,

Andreas

[embedholic]

End device goes to system off state for maximum power save mode.

It wakes up when door opens. but after sends door state and it enters system off again.

So it can wake after very long time since it went to sleep.

In such case, coordinator can ages out the end device.

How can manage this case ?

Best regards.

[AndreasF]

Hi.

The right way to handle this case is described in the Zigbee specification, chapter 3.6.10.9 Diagrams Illustrating End Device Management. You can take a look at the light switch example as an reference to handling leave signal and rejoining. However, sleepy end device can be configured to poll parent rarely while sleeping so the power consumption is kept as low as possible and device is not aged by the parent. With longest ED_AGING_TIMEOUT and using recommendation to poll three times in aging_timeout period, may end up polling parent once per 4 days.

 Best regards,

Andreas