Network is an interconnection between computers using wired or wireless medium. In wireless, major difficulty faced by the system is transmission of data from one system (node) to another system (node) as compared to wired. In recent years many researchers are working towards data transmission in two major areas of wireless network: one is Wireless AdHoc Network and another is Wireless Sensor Network (WSN). Another and the main problem of WSN is Network lifetime (i.e. how long sensor nodes can survive on battery which are embedded in them). So to overcome these two problems researchers have proposed many protocols and they succeeded upto some extent. In this paper Threshold-sensitive Energy Efficient Network (TEEN) protocol discussed and implemented and then graph is drawn with respect Number of dead nodes Vs Number of rounds, where in every round, head nodes are getting change after some interval of time (Cluster Period).