If you do not want to create your own custom Role Provider and use the ASP.NET Membership’s in built RoleManager. Then you should use the following setting in your web.config file.

<roleManager enabled="true" defaultProvider="SqlRoleProvider" >
  <providers>
    <add name="SqlRoleProvider"
         type="System.Web.Security.SqlRoleProvider"
         connectionStringName="AbcAspNetConnection"
         applicationName="Abc Web Application"/>
  </providers>
</roleManager>