The growth of the Internet and the intranets and the availability of low cost broadband services are now making multimedia applications over the Internet a viable option. Interactive real-time multimedia applications such as video over IP, voice over IP, Web learning among others, require guaranteed and predictable QoS. The introduction of differentiated services (DiffServ or DS) mechanism as a low cost simple model on Internet routers has immediate impact on critical-mission applications with respect to QoS and traffic engineering (TE). Differentiated services provides for aggregate traffic to be classified and conditioned at the edge of the network routers on the basis of performance. Core routers simply deal with scheduling and processing traffic aggregates only. (Most of the computations are done at the edges). We evaluate the performance of a new service model based on differentiated services approach. Real-time interactive multimedia traffic simulated under different traffic conditions. A performance comparison of the new service model routing method to the existing IP routers are done using OPNET simulator.