+------+                              +------+
|Client|                              |Server|
+------+                              +------+
   |=======QUOTATION(Requested CPD)=====>|
   |<========PROCESSING(time1)===========|
                     ...
   |<========PROCESSING(MoreTime)========|
   |============ACK(TimeGranted)========>|
                     ...
   |<=========OFFER(Offered CPD)=========|
   |=============PROCESSING=============>|
   |=========ACCEPT(Accepted CPD)=======>|
   |<=========ACK(Accepted CPD)==========|
   |                                     |