+---------------------+
                              | Client              |
                              |                     |
   +---(A) Token request------| Client -            |
   |                          | Authorization       |
   |   +-(B) Access token-----> Server Interface    |
   |   |                      |       (HTTPS)       |
   |   |                      |_____________________|
   |   |                      |                     |
+--v-------------+            |  Pub/Sub Interface  |
|  Authorization |            |   (MQTT over TLS)   |
|  Server        |            +----------------^----+
|________________|                 |           |
   |    ^                 (C) Connection   (F) Connection
   |    |                     request +        response
   |    |                     access token     |
   |    |                          |           |
   |    |                      +---v--------------+
   |    |                      |     Broker       |
   |    |                      |  (MQTT over TLS) |
   |    |                      |__________________|
   |    +(D) Introspection-----|                  |
   |         request (optional)| RS-AS interface  |
   |                           |     (HTTPS)      |
   +-(E) Introspection-------->|__________________|
         response (optional)