Recently, there has been a lot of interest in the research community (IRTF / IETF) towards parallely implementing and standardizing a new TCP extension called TCP Prague, which is targeted to be an evolution of Data Center TCP (DCTCP). DCTCP starves the throughput of other TCP flows (e.g., Reno, Cubic, etc) when they co-exist; so one of the goals is to ensure that TCP Prague can co-exist with other TCP flows without degrading their throughput. Although TCP Prague is still a work in progress, some related modules have been finalised and briefly experimented, such as: the Low Latency, Low Loss, Scalable throughput (L4S) service architecture, DualQ Coupled AQM, Modified ECN Semantics for Ultra Low Queueing Delay. Availability of these modules in network simulators like ns-3 is crucial to boost up the ongoing efforts of standardizing TCP Prague. In this project, the aim is to implement the above mentioned modules in ns-3. Additionally, the functionality of these modules will be tested, and the necessary documentation with some examples will also be provided.