In this paper, we present a 3-D correlated algorithm for reducing Semi-Markov Process (SMP) with very large state space in Mobile Ad Hoc Network (MANETS). We introduce a correlated state transition for Node Behavior Model based on 3-D Markov chain. Intuitively, node in MANET will be grouped according to its correlated state behavior. Thus, uncorrelated state will be discarded. The result shown correlated algorithm has reduced computational processing as well as energy consumption. These will prolong node's lifetime and enhance network survivability.