SCTE 104/35 Codex

The 12-bit tier field lets a message provider tag each SCTE 35 message with an authorization tier so downstream equipment can filter which messages it acts on. Any value from 0x000 to 0xFFF is allowed; the value 0xFFF is kept for backward compatibility and is simply ignored by downstream equipment rather than filtering by tier. When tier is used, the whole message should fit in a single transport packet.