--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/programming/connect.rst	Wed Apr 03 13:02:50 2024 +0200
@@ -0,0 +1,98 @@
+Connect IDE to Runtime
+======================
+
+
+Connection is described by the *URI_location* in project's configuration.
+    ``Open project tree root -> Config tab -> URI_location``
+
+eRPC
+----
+
+`eRPC <https://github.com/embeddedrpc/erpc>`_ (Embedded RPC) is an open source
+Remote Procedure Call (RPC) developed by NXP. 
+
+In case of Beremiz, Runtime is the eRPC server and IDE is a client. Transport
+can be either TCP/IP or Serial.
+
+``URI_location`` for eRPC:
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    * ``ERPC://host[:port]`` unencrypted connection. Default port is 3000.
+        This connection is highly unsecure, and should never be used on
+        untrusted network. It is intended to be used on peer to peer connection
+        such as ethernet over USB, for initial pairing with IDE.
+    * ``ERPCS://host[:port]`` SSL-PSK encrypted connection.
+        Default port is 4000.
+    * ``LOCAL://`` starts local runtime and connect with it through TCP/IP
+        bound to Localhost using random port.
+
+SSL-PSK setup:
+^^^^^^^^^^^^^^
+
+In order to provide practical secure communication in between runtime and IDE
+TLS-PSK connection according to rfc4279.
+
+Server (runtime)
+""""""""""""""""
+.. highlight:: ini
+
+PSK ciphersuite avoids the need for public key operations and certificate
+management. It is perfect for a performance-constrained environments with
+limited CPU power as a PLC.
+
+`Stunnel <https://www.stunnel.org/>`_ is used to wrap unencrypted eRPC server
+into an TLS-PSK SSL socket. Hereafter is ``stunnel.conf``::
+
+    [ERPCPSK]
+    accept = 4000
+    connect = 127.0.0.1:3000
+    ciphers = PSK
+    sslVersion = TLSv1.2
+    PSKsecrets = psk.txt
+
+.. highlight:: text
+
+List PSK ciphers available in server's openssl::
+
+    openssl ciphers -s -psk -tls1_2
+
+Launch ``stunnel``::
+
+    stunnel ./stunnel.conf
+
+Client (IDE) 
+""""""""""""
+
+Compare client's available openssl PSK ciphers with Server's ciphers. At least
+a few of them should match::
+
+    openssl ciphers -s -psk -tls1_2
+
+Use unencrypted peer-to-peer connection such as network over USB 
+or simple Ethernet cable, connect an obtain PSK::
+
+    ERPC://hostname[:port]
+
+Then use Identity Management dialog in IDE to select matching ID and generate
+``ERPCS`` URI::
+
+    ERPCS://hostname[:port]#ID
+
+
+WAMP
+----
+
+`WAMP <https://wamp-proto.org/>`_ is an open standard WebSocket subprotocol that provides two application messaging 
+patterns in one unified protocol: Remote Procedure Calls + Publish & Subscribe.
+
+Beremiz WAMP connector implementation uses python ``autobahn`` module, from the `crossbar.io <https://github.com/crossbario>`_ project.
+
+Both IDE and runtime are WAMP clients that connect to ``crossbar`` server through HTTP.
+
+``URI_location`` for WAMP:
+	* ``WAMP://host[:port]#realm#ID`` Websocket over unencrypted HTTP transport.
+	* ``WAMPS://host[:port]#realm#ID`` Websocket over secure HTTPS transport.
+
+
+..
+    TODO : 
+        crossbar server setup with example config and minimal backend.