Reducing Internet Transport Latency is an interesting research topic and has gained significant attention in the recent past. Some of the promising new solutions rely on Explicit Congestion Notification (ECN) (RFC 3168) to notify TCP endpoints of congestion that may be developing in a bottleneck queue, without resorting to packet drops. As a result, there have been attempts at Internet Engineering Task Force (IETF) to extend the functionality of ECN and provide rich feedback to TCP endpoints. In this regard, Accurate ECN feedback (AccECN) and ECN++ are two active topics of discussion at IETF. This project proposal is to: extend the ECN implementation in ns-3 to support AccECN and ECN++, test the correctness of implementation and provide examples.