[19263] User configuration for SHM metatraffic

code/DDSCodeTester.cpp

@@ -787,6 +787,17 @@ void dds_domain_examples()
             "true");
         //!--
     }
+
+    {
+        // DDS-SHM-ENFORCE-META-TRAFFIC
+        DomainParticipantQos participant_qos;
+
+        // SHM transport will listen for unicast meta-traffic
+        participant_qos.properties().properties().emplace_back(
+            "fastdds.shm.enforce_metatraffic",
+            "unicast");
+        //!--
+    }
 }
 
 //DOMAINPARTICIPANTLISTENER-DISCOVERY-CALLBACKS

code/XMLTester.xml

@@ -3282,6 +3282,21 @@
 </participant>
 <!--><-->
 
+<!-->XML-SHM-ENFORCE-META-TRAFFIC<-->
+<participant profile_name="participant_xml_conf_shm_enforce_metatraffic_profile">
+    <rtps>
+        <propertiesPolicy>
+            <properties>
+                <property>
+                    <name>fastdds.shm.enforce_metatraffic</name>
+                    <value>unicast</value>
+                </property>
+            </properties>
+        </propertiesPolicy>
+    </rtps>
+</participant>
+<!--><-->
+
 <!-->XML_TYPELOOKUP_SERVICE_ENABLING<-->
 <participant profile_name="participant_typelookup_service_enabled">
     <rtps>

docs/fastdds/property_policies/non_consolidated_qos.rst

@@ -297,3 +297,57 @@ Currently there are two different exchange formats which can be selected using t
            :language: xml
            :start-after: <!-->XML-STATIC-DISCOVERY-FORMAT
            :end-before: <!--><-->
+
+.. _property_policies_shm_enforce_metatraffic:
+
+SHM transport meta-traffic enforcement
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+A DomainParticipant will by default configure both a :ref:`transport_udp_udp` and a
+:ref:`transport_sharedMemory_sharedMemory`.
+When a participant on another process in the same host is discovered, the endpoint discovery
+might be done using either transport.
+
+Avoiding Shared Memory communication for discovery traffic can save valuable resources.
+The behavior regarding this can be configured using the property ``fastdds.shm.enforce_metatraffic``.
+
+.. list-table::
+   :header-rows: 1
+   :align: left
+
+   * - PropertyPolicyQos value
+     - Description
+     - Default
+   * - ``"none"``
+     - Use other transports for meta-traffic.
+     - ✅
+   * - ``"unicast"``
+     - Enable SHM transport unicast communications.
+     -
+   * - ``"all"``
+     - Enable SHM transport unicast and multicast communications. |br|
+       This will enable discovery between SHM only participants |br|
+       and participants having several transports.
+     -
+
+.. note::
+
+  When SHM is the only transport configured for a participant, the setting of this property is ignored,
+  and considered to be ``"all"``.
+
+.. tabs::
+
+    .. tab:: C++
+
+        .. literalinclude:: /../code/DDSCodeTester.cpp
+           :language: c++
+           :start-after: //DDS-SHM-ENFORCE-META-TRAFFIC
+           :end-before: //!--
+           :dedent: 8
+
+    .. tab:: XML
+
+        .. literalinclude:: /../code/XMLTester.xml
+           :language: xml
+           :start-after: <!-->XML-SHM-ENFORCE-META-TRAFFIC
+           :end-before: <!--><-->

docs/spelling_wordlist.txt

@@ -211,6 +211,7 @@ seqNum
 SequenceNumber
 sequencenumbers
 shm
+SHM
 simpleEDP
 sqlite
 statechart