  Narrowband Internet-of-Things (NB-IoT) is one of the major access
technologies proposed to support massive machine type communications (mMTC)
services for the 5th generation (5G) mobile networks. Many emerging services
and networking paradigms are expected to be developed on top of NB-IoT
networks. This paper summarizes the steps required to build up an open source
narrowband Internet-of-Things (NB-IoT) network. This work is a joint research
and development (R&D) result from industry and academic collaboration. The open
source NB-IoT enhanced Node B (eNB) is jointly developed by B-COM and NTUST
based on the well-known OpenAirInterfaceTM (OAI) open source Long-Term
Evolution (LTE) eNB developed by EURECOM. The NB-IoT eNB is successfully
connected to an evolved packet core (EPC) developed by Nokia Bell Lab. We
demonstrate how to use commercial off-the-shelf (COTS) NB-IoT module to forward
its sensing data to the Internet via the open source NB-IoT network.
