+---------------------+
    | server              |
    +---------------------+
    | admin-state         |   1..* +------------+
    | server-tcp-port     |<>------| key-chain  |
    | servwait            |        +------------+
    | control-packet-dscp |        | key-id     |
    | count               |        | secret-key |
    | max-count           |        +------------+
    | modes               |
    |                     |   0..* +--------------------------+
    |                     |<>------| ctrl-connection          |
    +---------------------+        +--------------------------+
                                   | client-ip           {ro} |
                                   | client-tcp-port     {ro} |
                                   | server-ip           {ro} |
                                   | server-tcp-port     {ro} |
                                   | state               {ro} |
                                   | control-packet-dscp {ro} |
                                   | selected-mode       {ro} |
                                   | key-id              {ro} |
                                   | count               {ro} |
                                   | max-count           {ro} |
                                   | salt                {ro} | 
                                   | server-iv           {ro} |
                                   | challenge           {ro} |
                                   +--------------------------+