The explosion of Internet services such as video on demand, big data, server virtualization and cloud services is among the trends driving the networking industry to change traditional network architectures to more flexible and dynamic schemes. Software Defined Networking is an emerging network architecture that could address the needs of services providers and networks operator. This new technology consist in decoupling the control plane from the data plane, enabling to centralize control functions in a concentrated or distributed platform. It also creates an abstraction between the network infrastructure and network applications that allows to design more flexible and programmable networks. However, in order to both services and network applications can run properly, a global and updated view of the network is required at every moment. This paper attempts to address the main protocols and approaches of the topology discovery service provided by the controller in a single administrative domain. Also the procedure of topology discovery in a network composed by non-OpenFlow and OpenFlow switches are presented. In addition, attention is focused on Layer 2 discovery protocols LLDP and BDDP and major limitations of these procedures are discussed.