This paper presents Multi-Protocol Label Switch (MPLS) as a promising network evolution technology to implement the transition from traditional ATM and IP network to the next generation optical Internet. As bandwidth-intensive services increase, and as the number of users connected to the Internet grows, traditional ATM and IP network, though with their own advantages, could hardly satisfy the ever-increasing requirements. Under such conditions, the network evolution is impending. MPLS, which integrates the control of IP routing on the layer 3 with the simplicity of Layer 2 switching, inheriting their advantages, and discarding their disadvantages, is deem as the most promising candidate for the network evolution technology. Furthermore, the recent research on MPLS traffic engineering provides an ideal solution to combine MPLS control plane with optical switching, and even to incorporate DWDM multiplexing capabilities in IP routers. The perspective of MPLS is further illustrated.