RFC 9562 §5.9 · §5.10 · §4.1
Nil, Max and the variants
Two special values outside the version system, and the two bits that say whether an id follows the RFC at all.
nil · a placeholder for “no id”
00000000000000000000000000000000
max · an upper bound for range queries
ffffffffffffffffffffffffffffffff
digit 17 tells the variant
| top bits | digit 17 | variant |
|---|---|---|
| 0xx | 0–7 | Apollo NCS (1980s) |
| 10x | 8 9 a b | RFC 9562, every version here |
| 110 | c d | Microsoft GUID |
| 111 | e f | reserved (Max lives here) |