What type of licenses are there?

From Backup Central

The licenses distinguish between evaluation, Not for Resale (NFR), and permanent. They also distinguish what version of NetBackup you bouth, whether the license is for NT or UNIX, and whether it is for the server, client, or is an add on module such as Oracle or NDMP.

I came here wondering something a lot of people do, though: what types of licenses need to be *installed* where?

From the installation manual: "All product license keys must be entered on the master server. However, some features and products require the keys to also be installed on the media server. The following list identifies features that require keys to be installed on the media servers in addition to the master servers. - NetBackup SAN Shared Storage Option (SSO) - Library-based Tape Drives Feature - Advanced Client"