Invitation rewards are decentralized and settled to the inviter immediately after the invitee completes registration. Due to the underlying principle of Nervos CKB, rewards need to be paid out only when a certain amount is reached. Also, since DAS is a smart contract running on Nervos CKB, it can only recognize the assets of Nervos CKB internally. In fact, the fees for the registration/renewal/administration/reward settlement actions are all paid in CKB. Therefore, promotional rewards are also issued in the form of CKBs. The rewards can be viewed and withdrawn from the administration interface of the registration service.