Call admission control (CAC) is an important technology for maintaining Quality of Service (QoS) in Software-Defined Networking (SDN). The most popular type of CACs is trunk reservation (TR) control, and many TR control methods had been proposed for improving evaluation values such as call blocking probability or the resource utilization rate. In general, some users under these TR control methods may behave cooperatively. However, conventional TR methods do not take into account a user's cooperative behavior when they begin to communicate. In this paper, we propose a novel TR-type CAC method by considering the cooperative behavior of some users. This proposed method is presented using the loss model of queueing theory for the call-level analysis of a single link. We also analyze the characteristics of the optimal control parameter.