Difference between correlation and parameterization

In Correlation the Dynamic Value is Generated by the Server.

In Parametrization the Value will be given by the User.

Brief:

When one wants to perform the script’s actions like submit using different values from those recorded.

 To do this, we can replace the recorded values with parameters.This is known as parameterizing the script.

Eg: Try to Login Yahoo Mail or Gmail with Multiple Username and Password in Load Runner.

Many applications and Web sites identify a session by the current date and time. If you try to replay a script,

 it will fail, because the current time is different than the recorded time.

Correlation is a concept where we can capture the dynamic data when it is generated and used

 throughout the script.

Eg: In IRCTC website, Login and check the URL. The URL consist of Session Value which is dynamically 

Generated by the Server and even developer cannot tell that "What the dynamic value is going to generated".