|Bit |  8 7  |     6       | 5 4 3 2 1    |
|-----------------------------------------|
|    | CLASS | CONSTRUCTED | TAG NUMBER   |
|--------|--------------------------------|
         |
         |
         +->     00 Universal           meaning is the same for all 
                                           applications; defined in X.208
                 01 Application         meaning is specific to an application
                 10 Private             meaning is specific to an enterprise
                 11 Context-Specific    meaning is specific to a given
                                           structured type

Figure 5: Breakdown of the identifier octet.