Кибернетика, автоматика, протоколы

 --keepalive interval timeout
              A helper directive designed to simplify the expression of --ping and --ping-restart.

              This option can be used on both client and server side, but it is enough to add this on the server side as it will push  appropriate  --ping
              and  --ping-restart  options to the client.  If used on both server and client, the values pushed from server will override the client local
              values.

              The timeout argument will be twice as long on the server side.  This ensures that a timeout is detected on client  side  before  the  server
              side drops the connection.

              For example, --keepalive 10 60 expands as follows:

                   if mode server:
                     ping 10                    # Argument: interval
                     ping-restart 120           # Argument: timeout*2
                     push "ping 10"             # Argument: interval
                     push "ping-restart 60"     # Argument: timeout
                   else
                     ping 10                    # Argument: interval
                     ping-restart 60            # Argument: timeout