The present document presents an overview of the architecture of the NFV Infrastructure (NFVI) which supports deployment and execution of Virtualised Network Functions (VNFs). As well as presenting a general overview description of the NFV Infrastructure@ the present document sets the NFV infrastructure and all the documents which describe it in the context of all the documents of the NFV. It also describes how the documents which describe the NFV infrastructure relate to each other. The present document does not provide any detailed specification but makes reference to specifications developed by other bodies and to potential specifications@ which@ in the opinion of the NFV ISG could be usefully developed by an appropriate Standards Developing Organisation (SDO). The overall objectives of the ISG NFV were set out in the white paper [i.1] that led to the founding of the ISG and updated in the white paper update [i.2].