IBM Rational® License Key Center shows two types of license keys for IBM Rational ClearCase®: "classic" Rational ClearCase keys, and Rational ClearCase keys based on FLEXlm software.
The term "classic" Rational ClearCase license keys refers to the proprietary license manager used by Rational ClearCase. This manager is also referred to as the "Rational ClearCase license manager." The license manager supports Rational ClearCase through version 7.1.
Version 7.1 offers the choice of using the classic Rational ClearCase license manager or using IBM Rational Common Licensing (powered by FLEXlm software). The benefit of using the license manager based on FLEXlm is that you can have a single Rational license server manage your Rational ClearCase, IBM Rational ClearQuest®, and other IBM Rational product license keys using Rational Common Licensing.