Windows of Time

Each table in this chapter identifies a data type for a Group Statistic: counter, gauge, config, timeticks, and period.

Note:

For more information about Group Statistic data types, see What is HDR?.

A period type represents a value determined as the sum of a number of events which occurred during a specified window of time (or a time period). There are three possible windows in which events can occur:

• current window
• previous window
• sliding window

The current window is the window during which events are currently being accumulated. The current window ends D seconds after the start of the current window, where D is the duration of the window. The current window is always of size Dc < D. Once the current window becomes of size D, it becomes the previous window, and a new current window is started.

The previous window is the time period of duration D which ended at the start of the current window.

The sliding window marks the period of time for the previous window, D, plus the time passed in the current window. For example: For the "session-agent" and "session-realm" HDR groups, the default timer value is 30 seconds. The "current window" is between 0 and 30 seconds. When the current window reaches 30 seconds it becomes the previous window and a new current window is initialized. The "sliding window" is the sum of the current window and previous window. Therefore the initial sliding window is between 0 and 30 seconds and after that the sliding window is between 30 and 60 seconds.

For the session-agent statistics and the session-realm statistics groups, the default period timer is 30 seconds. In the OCSBC configuration, if the sustained-rate-window parameter is not configured, the default window size is 30 seconds. If the sustained-rate-window parameter is configured, the default period is set to the configured value of the sustained-rate-window.