Recent years have shown an increased interest towards multimedia rich applications. Multimedia content ranges from text or simple images to audio data or video data. A Next-Generation Network (NGN) is a packet-based network that handles multiple types of traffic (such as voice, data, and multimedia). Multimedia applications include large amount of data, high throughput, and multiple flows which need diverse QoS characteristics. Nowadays, many applications use TCP as their transport protocol. As the network evolves, many improvements and modifications are proposed to make TCP meet various requirements. TCP, although powerful and effective, is not sufficient to satisfy real time applications because TCP emphasizes more on reliability than timeliness. In this paper a new Improvement on TCP (ITCP) protocol is presented. Source rate is regulated based on the feedback which is received from intermediate nodes. Furthermore, in order to satisfy the requirements of different multimedia applications, a weighted random early detection (WRED) mechanism is used. Loss probability is calculated based on the packets priority in a router and the result is sent to source then it regulates its rate based on the packet loss probability values. The proposed protocol was simulated in order to evaluate its performance. Simulation results indicate that the ITCP improves overall system throughput and reduces delay and packet loss.

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