|
   +----------+        |        +-----------------+
   | Endpoint |        |        | Call Processing |
   +----------+        |        +-----------------+
                       |
                       |
+----------------+     |       +--------------------+
| Key Distributor|     |       | Media Distributor  |
+----------------+     |       +--------------------+
                       |
     Trusted           |             Untrusted
     Entities          |             Entities
                       |