====== P4-REQ-21-9-007 ======

[[dido:99_annexes:annex-d-requirements:part-04:start| Return to Requirements]]

===== Statement =====

Each QoS profile mapping SHALL identify the expected history behavior.

===== Source =====

Part 4, Section 21.9: QoS Profile Requirements.

===== Rationale =====

History behavior determines how much communication history is retained for applicable DDS exchanges.

Explicit history expectations allow Phase 0 to retain sufficient information for downstream consumption, review, troubleshooting, or demonstration without making the behavior implicit.

===== Applies To =====

This requirement applies to:

  * QoS profile mappings;
  * applicable DDS Topics;
  * publishers and subscribers; and
  * communication history configuration.

===== Verification =====

Verification SHALL confirm that each QoS profile mapping identifies its expected history behavior.

Verification activities should include review checks confirming that:

  * the selected history expectation is stated;
  * retained history supports the intended communication purpose;
  * history settings are compatible with participating implementations; and
  * configuration is governed by the Phase 0 baseline.

===== Traceability =====

This requirement establishes the history expectation associated with each Phase 0 QoS profile mapping.

Related requirement identifiers:

  * [[dido:99_annexes:annex-d-requirements:part-04:p4-req-21-9-006]]
  * [[dido:99_annexes:annex-d-requirements:part-04:p4-req-21-9-008]]

Related source section:

  * [[fxdemo:04-part:21-phase-0-implementation-requirements:21-9-qos-profile-requirements:start]]

===== Status =====

Draft

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