ZeroMQ is an open source (LGPL) [http://www.zeromq.org/] socket/messaging framework. There is a Tcl binding [https://github.com/zeromq/zeromq1/blob/master/libtclzmq/zmq.c] for V1.0. Bindings for version 2.1 and 3.1 can be found at http://github.com/jdc8/tclzmq <>Interprocess Communication