Asio is a freely available, open source, cross-platformC++ library for network programming. It provides developers with a consistent asynchronous I/O model using a modern C++ approach. Boost.Asio was accepted into the Boost library on 30 December 2005 after a 20-day review. The library has been developed by Christopher M. Kohlhoff since 2003. A networking proposal based on Asio was submitted to the C++ standards committee in 2006 for possible inclusion in the second Technical Report on C++ Library Extensions (TR2).