When multiple Major versions of a Decision Service also contain different Effective and Expiration Dates, you can also instruct Corticon Server to execute a Decision Service according to a date specified in the request message. This specified date is called the Decision Service Effective Timestamp.

How Corticon Server decides which Decision Service to execute based on the Decision Service Effective Timestamp value involves a bit more logic than the Major Version number. Let's use a graphical representation of the three Decision Service Effective and Expiration Date values to first understand how they relate.

Figure 1. DS Effective and Expiration Date Timeline

As illustrated, the three deployed Decision Services have Effective and Expiration dates that overlap in several date ranges:  Version 1 and Version 2 overlap from July 1, 2013 through December 31, 2013. And Version 3 overlaps with both 1 and 2 in July-August 2013. To understand how Corticon Server resolves these overlaps, let's invoke Corticon Server with a few scenarios.