This paper describes the experience in teaching protocol engineering to senior bachelor degree and master degree students at the University of Indonesia (UI) during the last 15 years. The development of convergence of computing and telecommunication which have been shown in the evolution of WAN, GSM, 2G, 3G, WiMAX, LTE, 4G up to 5 are triggered by worldwide competition and collaboration among researchers and engineers from all over the world. Open source software, operating systems and network simulators have been used in many ways in improving the Internet Protocol. The trend is going towards big data mining based on wireless sensor networks and crowdsourcing based information. At the University of Indonesia, we have used NS-2 and NS-3 as the de facto open source network simulator. In 2018, our work on the LoRaWAN, NB-IoT and Blockchain are based on NS-3. We have trained the next information infrastructure engineers using open source simulator. Meanwhile, cellular communications are evolving toward the fifth generation (5G). For testing the 5G network, we use The OpenAirInterface as the experimental platform to teach and to learn mobile communication networks. In delivering networking course at the UI, a comprehensive case study experience has led to a significant enhancement in teaching process, capability of students to master networking skills. The use of open source tools is more flexible, cheaper and available to be used for protocol engineering. We review the phases of installation, contributed code development, testing, and functions of 5G technology using the OpenAirInterface and NS-3. We present the result of the comparison of those tools.