7. If the serving MD-IS and the home MD-IS belong service providers who have no business arrangement, the serving MD-IS may not bother sending the RDR message. In this case, the serving MD-IS could possibly return a negative result code to the M-ES in the ISC message. Usually, however, the serving MD-IS would be expected to try to provide service and the home MD-IS would make the go/no-go decision.
