Data communication networks are among the most important and influential global infrastructures that humanity has created and an always growing number of physical objects are being connected to the Internet at an unprecedented rate, posing new challenges every day.The purpose of DCNET 2020 is to bring together researchers, engineers and practitioners to present and discuss ideas, challenges and potential solutions on established or emerging topics related to research and practice in the areas of computing, communications, and informatics. DCNET encompasses a diversity of topics, covering almost every aspect related to data communication: from network architecture and protocols to network management, monitoring and control, performance analysis, sensor nets, services over networks, LANs and WANS, IoT, vehicular communication, emerging communication technologies, Data Center networks, up to higher education in the data communication field.