The National Broadband Network (NBN) is an Australian national wholesale open-access data network project. It includes wired and radio communication components rolled out and operated by NBN Co Limited. Internet service providers, known under NBN as retail service providers or RSPs, contract with NBN to access the network and sell fixed internet access to end users.Rationales for this national telecommunications infrastructure project included replacing the existing copper cable telephony network that is approaching end of life, and the rapidly growing demand for internet access. As initially proposed in 2009, wired connections would have provided up to 100 Mbit/s (later increased to 1000 Mbit/s), with 98% of Australian households having a fibre to the node (FTTN) connection. This would have supplied a minimum of 12 Mbit/s, which was increased to a minimum of 25 Mbit/s in 2013 after the election of the Abbott government.As the largest infrastructure project in Australia's history, NBN was the subject of significant political contention and was an issue in federal elections. The Liberal party initially stated that the "Multi-Technology Mix" (MTM) would be completed by 2016, however this was changed after the election to 2019 and then again to 2020. The project cost jumped from the Liberal Party's estimated $29.5 billion before the 2013 federal election, to $46–56 billion afterwards. In 2016 NBN Co. said it was on target for $49 billion, but by late 2018 the estimated final cost was $51 billion.