Minecrafts hostile mobs and cliffs?

When designing a shelter in Minecraft, I've noticed zombies, skeletons, and creepers will jump off certain heights of cliffs to get to me. My question is: how high does a cliff have to be for them not to jump? Or are they aggressive to the very end?

They can jump at any height. The reason the don't jump for you at some cliffs is because they can't see you in the game.

Zombies, Skeletons, and Creepers can jump any 1 block high barrier, as long as it's not a fence. I'm not too sure if they'll actually jump off cliffs, because as far as I know, they won't jump off high heights to get you; their advanced AI will usually allow them to find alternative routes to reach you. And yes, hostile mobs will remain hostile towards you unless they can't see you.