RedRelay is a C++ networking library reimplementing Lacewing Relay protocol - an IRC-like protocol where peers have their unique IDs and names, can join channels and transmit data packets through TCP or UDP - can be used for chat, games, VoIP, data sharing, etc.
It is cross-platform and allows to use it not only in C++, but also as a Clickeam Fusion extension, or, for example, in Lua.
RedRelay is completely open-source, licensed under zlib/libpng license, allowing you to use it in any commercial project, etc
Documentation for the client library can be found at doc/client.html