An efficient adaptive Cross-Layer interaction mechanism for TCP traffic over heterogeneous networks We present an effective end-to-end mechanism of interaction between link layer and TCP over wired/wireless network. The motivation for adopting this method is to overcome both sources of error, namely; channel errors and congestion errors. This mechanism is adaptive in nature where channel encoding parameters (i.e. coding rate) will vary based on the deterioration level in the channel conditions. It is worth to note that whatever TCP flavor is implemented at the end systems, the proposed algorithm will not impose any change to it. NS2 is used to simulate the heterogeneous networks and implement the proposed adaptive method. Extensive simulation experiments have been conducted to evaluate the performance of the proposed approach and examine against fixed FEC approach. The simulation results have proven the ability of the proposed scheme to track the changes in the wireless channel and provide the necessary level of redundancy for FEC coding. Hence, it optimally uses the available resources and at the same time it achieves the maximum possible throughput.