Davies independently developed a similar message routing concept in 1965. He coined the term "packet switching", and proposed building a commercial nationwide data network in the UK. He gave a talk on the proposal in 1966, after which a person from the Ministry of Defence (MoD) told him about Baran's work. Roger Scantlebury, a member of Davies' team met Lawrence Roberts at the 1967 Symposium on Operating Systems Principles and suggested it for use in the ARPANET. Davies had chosen some of the same parameters for his original network design as did Baran, such as a packet size of 1024 bits. In 1966, Davies proposed that a network should be built at the laboratory to serve the needs of NPL and prove the feasibility of packet switching. To deal with packet permutations (due to dynamically updated route preferences) and to datagram losses (unavoidable when fast sources send to a slow destinations), he assumed that "all users of the network will provide themselves with some kind of error control", thus inventing what came to be known the end-to-end principle. After a pilot experiment in 1969, the NPL Data Communications Network entered service in 1970.