feat: hosting guide progress

docs/tutorials/hosting_guide.rst

@@ -2,12 +2,43 @@
 Advanced hosting
 ================
 
-WIP
+This tutorial aims to guide you to host a collaborative Session on internet.
+
+.. note::
+    This tutorial will change soon with the new dedicated server. 
+
+
+The multi-user network architecture is based on a clients-server model. The communication protocol use four ports to communicate with client:
+
+* Commands: command transmission (such as **snapshots**, **change_rights**, etc.)
+* Subscriber: pull data
+* Publisher: push data 
+* TTL (time to leave): used to ping each clients
+
+To know which ports will be used, you just have to read the port in your preference.
+
+.. image:: img/hosting_guide_port.png
+    :align: center
+    :alt: Port
+
+In the picture below we have setup our port to **5555** so it will be:
+
+* Commands: 5555 (**5555** +0)
+* Subscriber: 5556 (**5555** +1)
+* Publisher: 5557 (**5555** +2)
+* TTL: 5558 (**5555** +3)
+
+Now that we know which port are needed to communicate we need to allow other computer to communicate with our one. 
+By default your router shall block those ports. In order grant server access to people from internet you have multiple options:
+
+1. Simple: use a third party software like `HAMACHI <https://vpn.net/>`_ (Free until 5 users) or `ZEROTIER <https://www.zerotier.com/download/>`_ to handle network sharing.
+
+2. Harder: Setup a VPN server and allow distant user to connect to your VPN.
+
+3. **Not secure** but simple: Setup port forwarding for each ports (for example 5555,5556,5557 and 5558 in our case). You can follow this `guide <https://www.wikihow.com/Set-Up-Port-Forwarding-on-a-Router>`_ for example.
+
+Once you have setup the network, you can run **HOST** in order to start the server. Then other users could join your session in the regular way.
+
 
-Port forwarding
-===============
-
-For now, a session use 4 ports to run.
-If 5555 is given in host settings, it will use 5555, 5556 (5555+1), 5557 (5555+2), 5558 (5555+3