Tcl-DP adds TCP, UDP, and IP-multicast connection management, remote procedure call (RPC), and distributed object protocols to Tcl/Tk. A C interface to the RPC primitives is also provided.
I have used this package in a production environment for several years. It has never been the cause of any problems. None. That's actually pretty amazing. I *have* run into (say) Perl bugs, but Tcl-DP, none.
Several companies have for years relied on Tcl-DP for internal inter-process communications. Now the public version of Tcl-DP is back.