Escalation policies allows you to define a preset escalation path for any alert stream. Once an event is fired, escalation policy automatically assigns the alerts to first configured escalation point, and waits for configured time frame for alert to be acknowledged.
If an alert is not acknowledged within the set timeframe, next level of escalation is followed and the alert notifications are sent to the second level of escalation and so forth, until the escalation policy reaches the end of escalation process.
You can have many levels of escalation by combaning oncall schedules and manager contacts, so that right person is always alerted when alerts are not acknowledged within specific time frame and allowing you to improve your SLAs.
You can even configure escalation policies to be repeated or run only once.