Quantum communications is not only considered as the utimate solution to secure communication but also the foundation of distributed quantum computing, which promises solutions to some problems that could not be previously approached. Since quantum communications is at its infancy stage, there are not enough communication protocols to efficiently network plenty of quantum computers and support efficient and reliable quantum data transmission. In this talk, we will first present some basic knowledge for quantum communicatioms and then discuss the key ingredients in designing quantum communication protocols. After that, we will introduce some of our recent works on quantum communication protocols in routing layer and above. At last, we will discuss the opportunities and challenges in designing communication protocols for quantum data networks.