Abstract: Current architecture of the IP routers are under stress due to the high performance expectations and the quality delivery of data to the end-users. In this presentation I will bring some of the IP router performnace bottlenecks and how they are overcome in the newer routers. Especially I will concentrate on the QoS aspects of the router. The outline of the presentation is as follows: - Introduction to an IP router Routing protocol support Layer 2 support Layer 4 support IP Functionality - QoS in IP routers What is QoS ? Why QoS in Internet a problem? Background Integrated Services Model Differentiated Services Model - MPLS ? the 2 ½ layer What is wrong with IP? What is MPLS? Flavors of MPLS - References