Set dungeons are built the same way every time, same goes to the challenges, that the player has to master within each portal. It's enough to have the ring of royal grandeur activated within Kanais Cube. As soon as the player confronts the obelisk at the entrance to a set dungeon, and that player has an active 6-set-bonus, the dungeon is ready to enter. The ring of royal grandeur, which can be found in the horadric caches in Act 1 and which reduces the amounts of necessary set-items for the set-bonusses by one, works along with the set portals. Diablo 3 Patch 2.4 ramped up some sets, so they contain 6 pieces now. Overall there are 24 set portals in Diablo 3, just accessible by characters wearing 6 pieces of a class set. Set dungeons are special places that can be accessed wire set portals, which are found all over Sanctuary. Set dungeons were introduced by Blizzard with Diablo 3: Reaper of Souls Patch 2.4 and provide a nice challenge for demon hunters, witch doctors, wizard, crusaders, barbarians and monks.
General information about Set Dungeons General information about set portals in Diablo 3: RoS