When you create a new service, an access policy called "All" is automatically created for you. This policy allows unrestricted access to all parts of your service.
Occasinally, you may want to prevent certain subscribers from using certain parts of your service. For example, suppose you are offering a weather information service at http://svc.webservius.com/v1/acme/weather. Suppose also that most of the data you offer can be given away (subject to the usual Usage Plan restrictions you define), but that you have some very expensive historical weather data at http://svc.webservius.com/v1/acme/weather/Historical that you only want to give to your premium clients.
To accomplish this, first go to the Operations page for your service, and define an operation with the URL template "Historical". URL templates can be much more flexible and powerful than in this simple example. For more information, see the help topic on URL Templates.
After you've created the Operation, no further technical knowledge is needed. Go to the Access Policies page for your service, and create a new policy called "Restricted". Leave the "Historical" operation unchecked, but check the "*" (star) operation to allow access to all other parts of the service.
Now, when you create Packages for your service, use this new "Restricted" access policy. For your premium customers, you may still assign the unrestricted "All" policy by manually creating their subscriptions on the Subscriptions tab.