SWRA615A June 2019 CC1352P , CC1352R , CC2530 , CC2531 , CC2538 , CC2652P , CC2652R , CC2652R7 , CC2652RB , CC2652RSIP
The Parent Announce message is now mandatory on all routing devices (router and coordinator) and is used to notify other routing devices in a network of which child devices are known to it. The message is broadcast to 0xFFFC if a routing device previously in the network was rebooted and successfully rejoins the network. It is sent 10 to 20 seconds after this device rejoins the network.