The rules permit a senator, or a series of senators, to speak for as long as they wish and on any topic they choose, unless "three-fifths of the Senators duly chosen and sworn"[1] (usually 60 out of 100 senators) brings debate to a close by invoking cloture under Senate Rule XXII.
So Cruz can hand off to Lee who can hand off to Paul, etc. It will be fun.
Idon’ really know what I’m talking about, but I assume that once Cruz has the floor he can talk as long as he wishes. That is I don’t think he can be interrupted for a cloture vote, however if he requests to yield to another senator, perhaps at that time a cloture vote can be taken? I say this because I doubt that there will be many people in the room when he is well into his filibuster, but at any time if you have 3/5 of democrats in the room, a cloture could stop the filibuster.