In an SDN/NFV-enabled network, the behavior of virtual switches is a major concern in determining the overall network performance. The prominent open-source solution for virtual switching is Open vSwitch while the DPDK library has been developed to accelerate the packet processing. In this paper, we develop a general framework for the modeling and the analysis of DPDK-based virtual switches, taking into account the switch-over times (amount of time needed for a CPU core to switch from one input queue to another). Our model delivers performance metrics such as the buffer occupancy, the loss rate and the sojourn time of a packet in RX queues. We compare our new model with two existing models. Numerical results show that our model combines the accuracy of one model and the efficiency of the other.