It is only 1.5 rounds and not 2.5 rounds.. Bisping is a pretty durable guy and does know how to survive off his back....
Luke should finish before 5 rounds though I think.. Luke really is in his prime right now and a bit of a beast.. Bisping is at the end of his career and coming in on short notice... Luke trained up and ready for Weidman is scary..
Anderson Silva couldn't KO Bisping though.. Just a little worried about Luke going for an early take down because he's wrestled up for Weidman and then start beating on Bisping from the top position and then work for a sub..
Remember Luke has most of his wins by submission..
http://www.sherdog.com/fighter/Luke-Rockhold-23345
Bisping was talking MAJOR smack on the UFC show where Luke had enough and just left.. With that being said Luke may just put a quick beating on Bisping..