namespace ara::com::e2e

The namespace ara::com::e2e defines types, states, and error codes for the end-to-end protection of adaptive communication. Consuming applications evaluate received data samples based on ProfileCheckStatus as well as SMState and may only use data if the state is kValid ([SWS_CM_90422]). On the provider side, errors such as deadline violations or packet loss can be monitored via TransportFaultConditionHandler ([SWS_CM_00091]). Erroneous states are mapped in a standardized way via the error domain ComE2EErrorDomain.

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Context

The namespace ara::com::e2e provides data types, status enumerations, and error handling structures for End-to-End protection (E2E) in the communication module of AUTOSAR Adaptive. Its primary task is to capture transmission and data integrity errors at the application and transport layers in a transparent and standardized manner.

Within the communication architecture, the namespace interacts with several key components:

• Service Provider (Skeleton): On the provider side, error conditions of the transmission can be monitored via function pointers. The type TransportFaultConditionHandler ([SWS_CM_00092]) allows registering and unregistering corresponding monitoring callbacks for all methods of a skeleton (AUTOSAR_AP_EXP_SWArchitecture p. 68) as well as for getter and setter calls of individual skeleton fields (AUTOSAR_AP_EXP_SWArchitecture p. 69).
• Consumers and Event Data (SamplePtr): On the consumer side, received data samples undergo an E2E check. The check result of an individual sample is mapped via ProfileCheckStatus ([SWS_CM_90421]), while the overall state of the monitoring is captured via SMState ([SWS_CM_90422]).
• Error Handling: The error domain ComE2EErrorDomain (AUTOSAR_AP_EXP_ARAComAPI p. 9) and the associated error codes ComE2EErrc ([SWS_CM_10474]) seamlessly integrate E2E errors into the error architecture model of ara::core. The class ComE2EException exists for exception handling.

Context diagram: Interaction between service provider (Skeleton), sample management (SamplePtr), and the error domain ara::com::e2e. Sources: AUTOSAR_AP_EXP_SWArchitecture p. 68, [SWS_CM_90421], [SWS_CM_10474].

Lifecycle and State Monitoring

E2E monitoring has a state-based lifecycle phase that is coupled with the reception of data samples via an event. The state is represented by the enumeration SMState ([SWS_CM_90422]):

• kInit: After initialization, not enough data samples with a successful E2E check are available yet; samples must not be used.
• kValid: Communication of data samples is functioning properly according to the E2E check; samples may be consumed.
• kInvalid: Too few error-free or too many erroneous samples were received within the E2E time window; samples must not be used.
• kNoData: No data has been received from the publisher yet.
• kStateMDisabled: The E2E state machine is administratively disabled.
• kIncompatibleQoS: Configured Quality of Service (QoS) policies of both communication endpoints do not match.

In parallel, ProfileCheckStatus provides the cycle status of the individual data sample ([SWS_CM_90421]): In addition to the success state kOk, the check distinguishes counter repetitions (kRepeated), illegal counter jumps (kWrongSequence), and data check errors (kError such as CRC, length, or Data ID errors). If the check is disabled, kCheckDisabled is returned.

As a fundamental precondition for data processing: A received data sample may only be used by the application if SMState == kValid applies and the check of the data sample (GetProfileCheckStatus) did not result in an error (kError) ([SWS_CM_90422]).

Usage Path

A typical usage path spans checking received event data on the consumer side and configuring transport error notifications on the provider side:

1. Status query of the data sample: After receiving a data sample via ara::com::SamplePtr, the consuming application calls GetProfileCheckStatus() to determine the specific check result of the sample ([SWS_CM_90421]).
2. State check of the monitoring: The application calls GetSMState() to query the aggregated state of the E2E state machine ([SWS_CM_90422]).
3. Processing or error handling: If SMState == kValid is present and no error was reported, payload processing takes place ([SWS_CM_90422]). Otherwise, the E2E error is handled via standardized error structures or forwarded by means of MakeErrorCode ([SWS_CM_12511]).
4. Transport error handling on the skeleton: Service providers register a TransportFaultConditionHandler to monitor their methods and field operations ([SWS_CM_00092], AUTOSAR_AP_EXP_SWArchitecture p. 68, AUTOSAR_AP_EXP_SWArchitecture p. 69). If a transport-related error occurs, the callback is invoked with the respective TransportFaultCondition ([SWS_CM_00091]).

Sequence diagram: Call sequence for validating received data samples and handling errors. Sources: [SWS_CM_90421], [SWS_CM_90422], [SWS_CM_12511].

Error Scenarios

In case of an error, the namespace provides two separate mechanisms that map different error sources:

Transport errors are signaled via the enumeration TransportFaultCondition ([SWS_CM_00091]):

• kSampleRejected: A data sample was dropped at layer 4 or above due to resource exhaustion at the endpoint.
• kDeadlineMissed: A data sample exceeded its configured deadline interval.
• kSampleLost: Loss of data samples was detected (for example, a gap in sequence numbers).

Protocol and check errors of the E2E transformation are classified via ComE2EErrc ([SWS_CM_10474]). These error codes include counter repetitions (kRepeated), counter jumps beyond the allowed delta (kWrongSequence), CRC/length errors (kError), missing new data (kNoNewData), and remote service errors (kUnspecifiedE2EError). The function MakeErrorCode serves to construct instances of type ara::core::ErrorCode ([SWS_CM_12511]), while GetComE2EErrorDomain returns a reference to the singleton instance of ComE2EErrorDomain ([SWS_CM_12510]). Interpretation: The class ComE2EException is likely used primarily when errors are mapped in execution paths with C++ exceptions enabled. Question Q-8eaebde6d1182f66 (open)