-X}-   : traffic from satellite terminal X to the server
={X+Y= : traffic from X and Y combined sent from 
         the server to terminals X and Y  

+-----------+        +-----+                
|Sat term A |--A}-+  |     |                           
+-----------+     |  |     |      +---------+      +------+
    ^^            +--|     |--A}--|         |--A}--|Coding|
    ||               | SAT |--B}--| Gateway |--B}--|Server|
    ===={A+B=========|     |={A+B=|         |={A+B=|      |
    ||               |     |      +---------+      +------+
    vv            +--|     |                           
+-----------+     |  |     |                           
|Sat term B |--B}-+  |     |                
+-----------+        +-----+