When you install or upgrade to NetWare 6, NLS is automatically installed. For a NetWare 6 server in a new eDirectory tree, no other action concerning the licensing service is required.
For fault tolerance, you should have NetWare 6 (or NLS) running on a second server in same partition as the other server.
NLS-enabled applications can use the licensing service. See the product-specific documentation for information about implementing the licensing services for that product.