+-------------------------------------------+
            |                                           |
            | Client                             Server |
            |                                           |
Handshake   |     --------- Q4S BEGIN ----------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
Negotiation |                                           |
(Stage 0)   |     --------- Q4S READY 0---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |                                           |
            |     <-------- Q4S-ALERT ------------      |
            |     -------- Q4S-ALERT ------------>      |
            |          (alert-pause start)              |
Repetition  |                                           |
of Stage 0  |     --------- Q4S READY 0---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |                    ...                    |
Negotiation |                                           |
(Stage 1)   |     --------- Q4S READY 1---------->      |
            |     <-------- Q4S 200 OK -----------      |
            |                                           |
            |     --------- Q4S BWITDH ---------->      |
            |     <-------- Q4S BWIDTH------------      |
            |                    ...                    |
            |                                           |
Continuity  |     --------- Q4S READY 2 --------->      |
            |     <-------- Q4S 200 OK -----------      | app start
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |(alert-pause expires &                     |
            |                   violated constraints)   |
            |     <-------- Q4S-ALERT ------------      |
            |     --------- Q4S-ALERT ----------->      |
            |                                           |
            |           (alert-pause start)             |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |     --------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |(alert-pause expires &                     |
            |                   violated constraints)   |
            |     <-------- Q4S-ALERT ------------      |
            |     --------- Q4S-ALERT ----------->      |
            |           (alert-pause)                   |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |(alert-pause expires &                     |
            |                 Fulfilled constraints)    |
            |                                           |
            |           (recovery-pause start)          |
            |                                           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |(recovery-pause expires &                  |
            |                 Fulfilled constraints)    |
            |     <--------- Q4S-RECOVERY ---------     |
            |     -------- Q4S-RECOVERY ----------->    |
            |                                           |
            |          (recovery-pause start)           |
            |     --------- Q4S PING ------------>      |
            |     <-------- Q4S 200 OK -----------      |
            |     <-------- Q4S PING -------------      |
            |      -------- Q4S 200 OK ---------->      |
            |                    ...                    |
            |                                           |
Termination |     --------- Q4S CANCEL ---------->      | app end
            |     <-------- Q4S CANCEL -----------      |
            |                                           |
            +-------------------------------------------+