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18.4 INAP SIGNALING 565TABLE 18.4-1 CS-1 OperationsCS-1 OperationsAddEntryApplyChargingCallInformationReportCallInformationRequestConnectDirectoryBindDirectoryUnbindFurnishChargingInformationInitialDPInitiateCallAttemptOAnswerOCalledPartyBusyODisconnectPlayAnnouncementReleaseCallRemoveEntrySendChargingInformationTAnswerTBusyTDisconnectRelationshipSCF ! SDFSCF ! SSFSSF ! SCFSCF ! SSFSCF ! SSFSCF ! SDFSCF ! SDFSCF ! SSFSSF ! SCFSCF ! SSFSSF ! SCFSSF ! SCFSSF ! SCFSCF ! SRFSCF ! SSFSCF ! SDFSCF ! SSFSSF ! SCFSSF ! SCFSSF ! SCFThe IN application uses operations to realize its services (Chapter 14) [21], witheach ASE responsible for one or more operations. INAP AEs send requests to invokeoperations and respond to requests with return results or with the invocation of otheroperations. Return results are returned for operations that request data from the recipientof the request, such as AddEntry, DirectoryBind, and RemoveEntry(Table 18.4-1); invokes are returned when a request asks for instructions on whatto do next. When operations fail or cannot be processed, AEs send back returnerror or reject notifications.Invokes, results, and error and reject notifications are transported in TCAP/SCCPor ISDN messages (see Chapters 16 and 10, respectively). INAP ASEs shape thosemessages via INAP-TCAP or INAP-ISDN primitives, which carry the operation parametersneeded by INAP services and the addressing information needed for deliveryof the messages.Each message type contains the appropriate parameters from the operation template:all types contain the Operation code (which identifies the operation), invokescarry the ARGUMENT, return results contain the RESULT, and return error notificationscontain the ERRORS parameter. Operation parameters are based on theROSE protocol, which is embedded in the Transaction sublayer of TCAP(Chapter 16), or in ISDN call-control messages [22,23]. More on ROSE and Operationparameters can be found in Section 14.1 and in [24–27].Figure 18.4-3, described in Section 18.4.6, shows how an operation invoke istranslated into a TCAP message and how the process is reversed at reception.INAP signaling is an Application layer (L7) protocol [28] and most commonlyuses TCAP and SCCP as transport mechanisms. The other allowed transport, the