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Take a look and let me know if you need clarification on anything. If you want to learn more about the logic for state changes, the following doc is really helpful (see the table at the bottom).check_interval: This directive is used to define the number of "time units" between regularly scheduled checks of the host. Unless you've changed the interval_length directive from the default value of 60, this number will mean minutes. More information on this value can be found in the check scheduling documentation.
retry_interval: This directive is used to define the number of "time units" to wait before scheduling a re-check of the hosts. Hosts are rescheduled at the retry interval when they have changed to a non-UP state. Once the host has been retried max_check_attempts times without a change in its status, it will revert to being scheduled at its "normal" rate as defined by the check_interval value. Unless you've changed the interval_length directive from the default value of 60, this number will mean minutes. More information on this value can be found in the check scheduling documentation