# Monitor requests

<dl class="api-definition">
<dt>Concept</dt>
<dd><a href="/docs/development/opcua/server/request-monitoring">Monitor requests</a></dd>
</dl>

| Type | Description |
|---|---|
| [IOpcServiceRequest](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.iopcservicerequest/) | Defines an interface which provides the header of the request of a service. |
| [IOpcServiceResponse](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.iopcserviceresponse/) | Defines an interface which provides the header and the success of the response of a service. |
| [OpcRequestImpeachment](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcrequestimpeachment/) | Defines the possible kind of impeachment a request can be confronted with before it is processed by the server. |
| [OpcRequestJudgementEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.services.opcrequestjudgementeventargs/) | Provides the event data for 'RequestJudgement' events. |
| [OpcRequestProcessedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestprocessedeventargs/) | Provides the event data for the [RequestProcessed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestprocessed) event. |
| [OpcRequestProcessedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestprocessedeventhandler/) | Represents the method which handles the [RequestProcessed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestprocessed) event. |
| [OpcRequestProcessingEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestprocessingeventargs/) | Provides the event data for the [RequestProcessing](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestprocessing) event. |
| [OpcRequestProcessingEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestprocessingeventhandler/) | Represents the method which handles the [RequestProcessing](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestprocessing) event. |
| [OpcRequestValidatedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestvalidatedeventargs/) | Provides the event data for the [RequestValidated](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestvalidated) event. |
| [OpcRequestValidatedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestvalidatedeventhandler/) | Represents the method which handles the [RequestValidated](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestvalidated) event. |
| [OpcRequestValidatingEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestvalidatingeventargs/) | Provides the event data for the [RequestValidating](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestvalidating) event. |
| [OpcRequestValidatingEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcrequestvalidatingeventhandler/) | Represents the method which handles the [RequestValidating](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#requestvalidating) event. |
| [OpcServer](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/) | Represents an OPC UA server which provides the address space defined by its [NodeManagers](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#nodemanagers) to its clients. |
| [OpcServerDiagnostics](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserverdiagnostics/) | Provides diagnostic summary information for the server. |
| [OpcServiceCounter](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcservicecounter/) | Provides diagnostic information about service calls. |
| [OpcSession](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsession/) | Represents a session which a client has created on the server. |
| [OpcSessionActivationFailedEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsessionactivationfailedeventargs/) | Provides the data of the [SessionActivationFailed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#sessionactivationfailed) event. |
| [OpcSessionActivationFailedEventHandler](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsessionactivationfailedeventhandler/) | Represents the method that handles the [SessionActivationFailed](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#sessionactivationfailed) event. |
| [OpcSessionDiagnostics](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsessiondiagnostics/) | Provides diagnostic information about client sessions. |
| [OpcSessionEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsessioneventargs/) | Provides the event data of the events related to an [OpcSession](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsession/). |
| [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsubscription/) | Provides information about a client initiated subscription. |
| [OpcSubscriptionDiagnostics](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsubscriptiondiagnostics/) | Provides diagnostic information about the operations performed and activities recognized on a [OpcSubscription](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsubscription/). |
| [OpcSubscriptionEventArgs](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcsubscriptioneventargs/) | Provides the event data for the [SubscriptionCreated](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#subscriptioncreated) and [SubscriptionDeleted](https://www.traeger.de/en/docs/development/opcua/api/v2.59/opc.uafx.server.opcserver/members#subscriptiondeleted) event. |