Restructuration of ROS 2 tutorials (#224)

Signed-off-by: Lucia Echevarria <[email protected]>

docs/rst/tutorials/core/ros2_tutorials.rst

@@ -12,6 +12,7 @@ This section provides a collection of tutorials on the use and application of th
     :maxdepth: 1
 
     wifi/wifi_tutorials
+    scalability/scalability_tutorials
     discoveryserver/discoveryserver_tutorials
     security/security_tutorials
     qos/qos_tutorials

docs/rst/tutorials/core/scalability/discovery_server/discovery_server_scalability.rst

@@ -0,0 +1,107 @@
+.. _tutorials_discovery_server_scalability:
+
+How to Use a Discovery Server to Optimize ROS 2 Node Discovery
+==============================================================
+
+.. contents::
+    :depth: 2
+    :local:
+    :backlinks: none
+
+Facing Scalability Challenges in Your ROS 2 System?
+---------------------------------------------------
+
+Have you ever struggled with scaling your ROS 2 network as it grows in size?
+As more nodes, topics, and services are added to a ROS 2 system, the underlying DDS (Data Distribution Service) quickly forms a fully-connected graph, meaning that every node discovers and communicates with every other node.
+While this setup guarantees robust connectivity, it can also lead to network congestion and high discovery traffic as the system scales, impacting performance and reliability.
+
+The Fast DDS Discovery Server offers a centralized mechanism for managing node discovery, allowing nodes to connect through a server instead of relying on the default multicast-based Simple Discovery Protocol (SDP).
+This reduces discovery traffic, provides better control over network management, and improves scalability in complex or large network scenarios.
+
+**Quick Solution Overview**
+
+Launch the Discovery Server locally on the default port (11811) using the following command:
+
+.. code-block:: bash
+
+    fastdds discovery
+
+Overview
+--------
+
+In this tutorial, we will explore how to set up and use the Fast DDS Discovery Server with ROS 2.
+Both a ``talker`` and a ``listener`` nodes from the ``demo_nodes_cpp`` ROS 2 package are created: the talker node will publish a "hello world" message every second, while the listener node will listen to these messages.
+By using the Discovery Server, nodes register and discover each other through a centralized server instead of communicating directly with every other node.
+
+.. figure:: /rst/figures/tutorials/core/discovery_server/Discovery_Server.svg
+   :align: center
+   :scale: 150%
+
+Background
+----------
+
+By default, ROS 2 uses the Simple Discovery Protocol (SDP), which relies on multicast communication to discover other nodes.
+While SDP is suitable for many scenarios, it may not be the best choice in complex and large-scale network configurations.
+This is where the Fast DDS Discovery Server comes into play. Fast DDS offers an alternative discovery mechanism that allows ROS 2 nodes to connect to a Discovery Server.
+This server acts as a centralized point for node registration and discovery, providing more flexibility and control in managing the network of nodes and is particularly advantageous in scenarios such as:
+
+* Large networks
+
+* Complex networks
+
+* WiFi networks
+
+In this tutorial, we will explore how to set up and use the Fast DDS Discovery Server with ROS 2, enabling robust and dynamic node discovery communication.
+
+Prerequisites
+-------------
+
+It is required to have previously installed Vulcanexus using one of the following installation methods:
+
+* `Linux binary installation <https://docs.vulcanexus.org/en/latest/rst/installation/linux_binary_installation.html>`__
+* `Linux installation from sources <https://docs.vulcanexus.org/en/latest/rst/installation/linux_source_installation.html>`__
+* `Docker installation <https://docs.vulcanexus.org/en/latest/rst/installation/docker.html>`__
+
+
+Run this tutorial
+------------------
+
+Once we finish with the set up of Vulcanexus environment we are ready to start with the *talker-listener* demo tutorial.
+By sourcing Vulcanexus you will get access to the CLI tool ``fastdds``, together with the ROS 2 environment.
+This tool gives access to the `discovery tool <https://fast-dds.docs.eprosima.com/en/latest/fastddscli/cli/cli.html#discovery>`__, which can be used to launch a discovery server.
+
+.. important::
+
+    Do not forget to source ROS 2 every time you open another session to have access to the ROS 2 environment and the CLI tool ``fastdds``.
+
+Setup Discovery Server
+^^^^^^^^^^^^^^^^^^^^^^
+Start by launching a discovery server on port 11811 (default port) and listening on all available interfaces.
+The role of the server is to re-distribute the clients (and servers) discovery information to their known clients (and servers).
+
+.. code-block:: bash
+
+    fastdds discovery
+
+
+Launch Talker Node
+^^^^^^^^^^^^^^^^^^^
+Execute the Talker demo to publish on the ``/chatter`` topic. When setting the ``ROS_DISCOVERY_SERVER`` environment variable you are indicating that ROS node should act as a client that connects to a discovery server to discover other nodes on the network.
+Use the argument ``--remap __node:=talker_discovery_server`` to change the node’s name for this tutorial.
+
+.. code-block:: bash
+
+    export ROS_DISCOVERY_SERVER=127.0.0.1:11811
+    ros2 run demo_nodes_cpp talker --ros-args --remap __node:=talker_discovery_server
+
+
+Launch Listener Node
+^^^^^^^^^^^^^^^^^^^^^
+Execute the Listener demo to listen to the ``/chatter`` topic.
+
+.. code-block:: bash
+
+    export ROS_DISCOVERY_SERVER=127.0.0.1:11811
+    ros2 run demo_nodes_cpp listener --ros-args --remap __node:=listener_discovery_server
+
+

docs/rst/tutorials/core/wifi/router_fully_connected/router_fully_connected.rst → docs/rst/tutorials/core/scalability/router_fully_connected/router_fully_connected.rst

@@ -2,8 +2,8 @@
 
 .. _tutorials_router_fully_connected:
 
-How to avoid Fully-Connected Graph Networks in ROS 2
-====================================================
+How to Use DDS Router for Scalable ROS 2 Network Communication
+==============================================================
 
 .. contents::
     :depth: 2

docs/rst/tutorials/core/scalability/scalability_tutorials.rst

@@ -0,0 +1,13 @@
+.. _tutorials_scalability_ros2_tutorials:
+
+Scalability and Large Scale Networks Tutorials
+==============================================
+
+Configuring ROS 2 applications over large networks can present multiple challenges.
+This series of tutorials is designed to help address common issues that arise when using ROS 2 over large networks, where factors such as latency, packet loss, and network congestion can significantly impact the functionality and performance of distributed systems.
+
+.. toctree::
+    :maxdepth: 1
+
+    discovery_server/discovery_server_scalability
+    router_fully_connected/router_fully_connected

docs/rst/tutorials/core/wifi/wifi_tutorials.rst

@@ -11,5 +11,4 @@ This series of tutorials is designed to help address common issues that arise wh
 
     wifi_issues_tutorial/wifi_issues_tutorial
     large_data/large_data
-    router_fully_connected/router_fully_connected
     image_compression/image_compression