From 33dc3758db9c10ceba4240a5f826c4bfa43bcf14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Ferreira=20Gonz=C3=A1lez?=
 <carlosferreira@eprosima.com>
Date: Fri, 9 Jan 2026 12:10:51 +0100
Subject: [PATCH 1/3] Refs #24015: Update keep alive docs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Carlos Ferreira González <carlosferreira@eprosima.com>
---
 code/DDSCodeTester.cpp                        | 17 +++++++
 code/XMLTester.xml                            | 15 ++++++
 docs/fastdds/transport/tcp/tcp.rst            |  8 ++--
 .../use_cases/ip_mobility/ip_mobility.rst     | 46 +++++++++++++++++++
 docs/fastdds/use_cases/use_cases.rst          |  6 +++
 docs/fastdds/xml_configuration/transports.rst |  8 ++--
 6 files changed, 92 insertions(+), 8 deletions(-)

diff --git a/code/DDSCodeTester.cpp b/code/DDSCodeTester.cpp
index cf472f97f..1ed290221 100644
--- a/code/DDSCodeTester.cpp
+++ b/code/DDSCodeTester.cpp
@@ -6521,6 +6521,23 @@ void dds_transport_examples ()
         //!--
     }
 
+    {
+        //CONF-TCP-KEEP-ALIVE
+        DomainParticipantQos qos;
+
+        // Create a descriptor for the new transport.
+        auto tcp_transport = std::make_shared<TCPv4TransportDescriptor>();
+
+        // Configure keep alive options
+        tcp_transport->keep_alive_frequency_ms = 5000;  // Send a keep-alive message every 5 seconds when connection is idle
+        tcp_transport->keep_alive_timeout_ms = 2000;  // Consider connection lost if no response is received within 2 seconds
+        tcp_transport->keep_alive_thread = eprosima::fastdds::rtps::ThreadSettings{-1, 0, 0, -1};  // Configure thread settings
+
+        // Link the Transport Layer to the Participant.
+        qos.transport().user_transports.push_back(tcp_transport);
+        //!--
+    }
+
     {
         //TRANSPORT-DESCRIPTORS
         DomainParticipantQos qos;
diff --git a/code/XMLTester.xml b/code/XMLTester.xml
index be156d0b7..ac32940a6 100644
--- a/code/XMLTester.xml
+++ b/code/XMLTester.xml
@@ -796,6 +796,21 @@
     </participant>
 <!--><-->
 
+<!-->CONF-TCP-KEEP-ALIVE<-->
+<!--
+<?xml version="1.0" encoding="UTF-8" ?>
+<profiles xmlns="http://www.eprosima.com">
+-->
+    <transport_descriptors>
+        <transport_descriptor>
+            <transport_id>keep_alive_transport</transport_id>
+            <type>TCPv4</type>
+            <keep_alive_frequency_ms>5000</keep_alive_frequency_ms>
+            <keep_alive_timeout_ms>25000</keep_alive_timeout_ms>
+        </transport_descriptor>
+    </transport_descriptors>
+<!--><-->
+
 <!-->CONF-DISABLE-MULTICAST<-->
 <!--
 <?xml version="1.0" encoding="UTF-8" ?>
diff --git a/docs/fastdds/transport/tcp/tcp.rst b/docs/fastdds/transport/tcp/tcp.rst
index a6d9eda87..181a264fa 100644
--- a/docs/fastdds/transport/tcp/tcp.rst
+++ b/docs/fastdds/transport/tcp/tcp.rst
@@ -93,12 +93,12 @@ The following table describes the common data members for both TCPv4 and TCPv6.
     - List of ports to listen as *server*. If a port is set to 0, an available port will be automatically assigned.
   * - |TCPTransportDescriptor::keep_alive_frequency_ms-api|
     - ``uint32_t``
-    - 5000
-    - Frequency of RTCP keep alive requests (in ms).
+    - 0
+    - |Pro| Frequency of RTCP keep alive requests (in ms).
   * - |TCPTransportDescriptor::keep_alive_timeout_ms-api|
     - ``uint32_t``
-    - 15000
-    - Time since sending the last keep alive request to consider a connection as broken (in ms).
+    - 0
+    - |Pro| Time since sending the last keep alive request to consider a connection as broken (in ms).
   * - |TCPTransportDescriptor::max_logical_port-api|
     - ``uint16_t``
     - 100
diff --git a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
index c08370a99..0e38d70c0 100644
--- a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
+++ b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
@@ -48,3 +48,49 @@ Please refer to :ref:`dds_layer_domainParticipantQos` for more information about
    (please refer to :ref:`remotelocatorsallocationattributes`).
    It is recommended to use the highest number of local addresses found on all the systems belonging to the same
    domain.
+
+.. _tcp-keep-alive:
+
+TCP Keep Alive |Pro|
+====================
+
+Fast DDS Pro additionally provides a TCP keep-alive mechanism to detect stalled TCP connections and recover from link failures
+more reliably.
+When enabled, the TCP transport periodically sends keep-alive requests on established TCP channels, and monitors
+activity to determine whether a connection is still responsive.
+Keep alive requests are sent only when no incoming data has been received for a specified interval.
+
+If the configured timeout is reached without observing activity after a keep-alive request, the channel is
+considered broken and is closed, allowing Fast DDS to reconnect and restore communication.
+
+Note that this feature operates at the application level, independently of any TCP keep-alive settings at the OS level.
+This allows for more fine-grained control over connection monitoring and recovery within Fast DDS.
+It also ensures consistent behavior across different operating systems and increases portability.
+
+Keep alive is disabled by default and can be configured through the following parameters in
+|TCPTransportDescriptor-api|:
+
+.. tab-set::
+
+    .. tab-item:: XML
+        :sync: xml
+
+        .. literalinclude:: /../code/XMLTester.xml
+            :language: xml
+            :start-after: <!-->CONF-TCP-KEEP-ALIVE<-->
+            :end-before: <!--><-->
+            :lines: 2-3, 6-
+            :append: </profiles>
+
+    .. tab-item:: C++
+        :sync: cpp
+
+        .. literalinclude:: ../../../../code/DDSCodeTester.cpp
+            :language: c++
+            :dedent: 8
+            :start-after: //CONF-TCP-KEEP-ALIVE
+            :end-before: //!
+
+.. note::
+
+   This feature is intended for TCP transports and only applies to connected TCP channels.
diff --git a/docs/fastdds/use_cases/use_cases.rst b/docs/fastdds/use_cases/use_cases.rst
index 008f136af..ee311ae9f 100644
--- a/docs/fastdds/use_cases/use_cases.rst
+++ b/docs/fastdds/use_cases/use_cases.rst
@@ -21,6 +21,12 @@ with distributed systems:
   If the network interfaces are expected to change while the application is running, *Fast DDS Pro* provides an
   automatic way of re-scanning the available interfaces and including them.
 
++ :ref:`TCP Keep Alive <tcp-keep-alive>` |Pro|.
+  In the same line as :ref:`IP mobility <ip-mobility>`, TCP Keep Alive feature allows to automatically detect
+  broken TCP connections by sending periodic keep-alive messages at application level when the connection is idle.
+  This feature is essential in TCP scenarios with dynamic IP changes or unstable network conditions,
+  ensuring that stale connections are identified and re-established promptly.
+
 + :ref:`use-case-tcp`.
   Describes how to configure *Fast DDS* to use the ``LARGE_DATA`` builtin transports mode.
   This mode enables efficient utilization of TCP transport without the need for constant reconfiguration
diff --git a/docs/fastdds/xml_configuration/transports.rst b/docs/fastdds/xml_configuration/transports.rst
index 70c46df5c..06f25cf77 100644
--- a/docs/fastdds/xml_configuration/transports.rst
+++ b/docs/fastdds/xml_configuration/transports.rst
@@ -84,13 +84,13 @@ A more detailed explanation of each of these elements can be found in :ref:`comm
      - ``string``
      -
    * - ``<keep_alive_frequency_ms>``
-     - Frequency in milliseconds for sending :ref:`RTCP <rtcpdefinition>` keep-alive requests (TCP only).
+     - |Pro| Frequency in milliseconds for sending :ref:`RTCP <rtcpdefinition>` keep-alive requests (TCP only).
      - ``uint32_t``
-     - ``50000``
+     - ``0``
    * - ``<keep_alive_timeout_ms>``
-     - Time in milliseconds since the last keep-alive request was sent to consider a connection as broken (TCP only).
+     - |Pro| Time in milliseconds since the last keep-alive request was sent to consider a connection as broken (TCP only).
      - ``uint32_t``
-     - ``10000``
+     - ``0``
    * - ``<max_logical_port>``
      - The maximum number of logical ports to try during :ref:`RTCP <rtcpdefinition>` negotiations (TCP only).
      - ``uint16_t``

From b565f54eb63944f929a6a31620582c7e1ef9a0a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Ferreira=20Gonz=C3=A1lez?=
 <carlosferreira@eprosima.com>
Date: Mon, 12 Jan 2026 08:33:24 +0100
Subject: [PATCH 2/3] Refs #24015: Fix doc8 tests
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Carlos Ferreira González <carlosferreira@eprosima.com>
---
 docs/fastdds/use_cases/ip_mobility/ip_mobility.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
index 0e38d70c0..63c5129e4 100644
--- a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
+++ b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
@@ -54,8 +54,8 @@ Please refer to :ref:`dds_layer_domainParticipantQos` for more information about
 TCP Keep Alive |Pro|
 ====================
 
-Fast DDS Pro additionally provides a TCP keep-alive mechanism to detect stalled TCP connections and recover from link failures
-more reliably.
+Fast DDS Pro additionally provides a TCP keep-alive mechanism to detect stalled TCP connections and recover
+from link failures more reliably.
 When enabled, the TCP transport periodically sends keep-alive requests on established TCP channels, and monitors
 activity to determine whether a connection is still responsive.
 Keep alive requests are sent only when no incoming data has been received for a specified interval.

From 7aeceb7252f470d061b9a826862f85ce5e2be215 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Ferreira=20Gonz=C3=A1lez?=
 <carlosferreira@eprosima.com>
Date: Fri, 6 Mar 2026 13:31:12 +0100
Subject: [PATCH 3/3] Refs #24015: Downgrade title section level
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Carlos Ferreira González <carlosferreira@eprosima.com>
---
 docs/fastdds/use_cases/ip_mobility/ip_mobility.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
index 63c5129e4..f615572f3 100644
--- a/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
+++ b/docs/fastdds/use_cases/ip_mobility/ip_mobility.rst
@@ -52,7 +52,7 @@ Please refer to :ref:`dds_layer_domainParticipantQos` for more information about
 .. _tcp-keep-alive:
 
 TCP Keep Alive |Pro|
-====================
+--------------------
 
 Fast DDS Pro additionally provides a TCP keep-alive mechanism to detect stalled TCP connections and recover
 from link failures more reliably.