Let us assume max discipline value of all items:
Belt - Hellcat Waistguard [Legacy] +8 Discipline
Ring - Stone of Jordan [Legacy] (Will only count once since it's unique equipped, meaning we can't equip two of them; can equip the Legacy version with the non-Legacy version) +8 Discipline
Ring - Stone of Jordan (Will only count once since it's unique equipped, meaning we can't equip two of them) +10 Discipline
Gloves - Frostburn Gauntlets +4 Discipline
Amulet - Xephirian Amulet +10 Discipline
Cloak - +10 Discipline
Quiver - +10 Discipline
1h Xbow - +10 Discipline
We can have a total of +70 Max Discipline, resulting in 100 Discipline with the 30 innate.