What does "Coordinator Realignment" do?

I'm not able to upload Ubiqua capture file to the forum.. said invalid file type... Just a screenshot.

Sounds like the command is used to send the orphan device the existing network information.

My situation is the ZC and ZED is pretty close to others (within 10 cm, no obstacle), only a ZED and a ZC was in the network. The ZED is not likely to lost connection to ZC. According to the capture file, it sends out orphan notification every 20-40s, and after receiving the "Coordinator realignment", ZED will reset itself (I've enable WDT, not sure the reset is caused by WDT or "Coordinator realignment").

Awaiting for your reply! Thanks.

What Z-Stack example does this ZED run?

Its zigbee mesh, I'm using GenericApp as template and have some modified

Does ZED run on CC2530DK or your own custom PCB? I would suggest you to run original GenericApp and see if you still see this issue.

Its a custom PCB. I'll give it a try.

Yes, please test with original GenericApp first.

I found out the reason, the ZED was reset by other IC on PCB, and when it rejoin the network, it first send out an orphan notification. Then the ZC reply with a Coordinator Realignment. 

Thanks again for your help YK Chen.

You are welcome.