====== P4-REQ-21-9-006 ======

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

===== Statement =====

Each QoS profile mapping SHALL identify the expected durability behavior.

===== Source =====

Part 4, Section 21.9: QoS Profile Requirements.

===== Rationale =====

Durability behavior determines whether and how previously published information remains available to later-joining participants.

Making this expectation explicit supports consistent Phase 0 review of late-joining behavior, replay-oriented review, status availability, and other communication needs.

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

This requirement applies to:

  * QoS profile mappings;
  * DDS publishers;
  * DDS subscribers; and
  * applicable Topic exchanges.

===== Verification =====

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

Verification activities should include review checks confirming that:

  * the selected durability expectation is stated;
  * the behavior supports the applicable communication purpose;
  * publisher and subscriber settings are compatible; and
  * the selected behavior is documented in the Phase 0 baseline.

===== Traceability =====

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

Related requirement identifiers:

  * [[dido:99_annexes:annex-d-requirements:part-04:p4-req-21-9-004]]
  * [[dido:99_annexes:annex-d-requirements:part-04:p4-req-21-9-007]]
  * [[dido:99_annexes:annex-d-requirements:part-04:p4-req-21-9-010]]

Related source section:

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

===== Status =====

Draft

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