--- a/src/source/architecture.rst	Mon Mar 26 11:12:28 2018 +0200
+++ b/src/source/architecture.rst	Mon Mar 26 17:29:25 2018 +0200
@@ -3,7 +3,19 @@
 PyAMS application architecture
 ==============================
 
-.. toctree::
-   :maxdepth: 2
+PyAMS applications are built on a small set of prerequisites and external components which *can* or, for some of them,
+*must* be included. Some of them are:
+
+* a mandatory shared ZODB;  :ref:`zodb` chapter
+
+* a Redis or Memcached server, to handle cache and sessions;
+    :ref:`pyams_cache` chapter
 
-   site
+* a websockets server (GuniCorn), used to handle desktop notifications; you can find information about this component in the
+  :ref:`pyams_notify` chapter;
+
+* an Elasticsearch index, used to handle quick and optimized searching.
+
+
+.. image:: _static/architecture.png
+