Forum Post: RE: How to get the extended pan ID at the application layer, when a router joins into a new network with zstack (zigbee pro), ?

Extended PAN ID is used for joining a specific zigbee network and is specified by manufacture. If you don't have Extended PAN ID specified on your zigbee device, it will choose any one proper to join. However, the Extend PAN ID won't be changed on your zigbee device.