NI has a protocol and code for efficient messaging over TCP/IP. The idea is to send a dictionary when you first connect, then binary messages subsequently for speed. Seems quite decent. I'm trying to decide if we should rework our NI DAQ protocol, and STM is a candidate. Since its an open protocol, we could use this for other interfaces too.
Current issues: Need a complete protocol spec so we can determine issues with other languages. In other words, it's easy in LabVIEW, but how much is a Java protocol engin?
STM intro: http://zone.ni.com/devzone/cda/tut/p/id/4095
App note: Multiple clients http://zone.ni.com/devzone/cda/tut/p/id/3055
Component and links: http://zone.ni.com/devzone/cda/epd/p/id/2739
Looks like no solution for C/C++/Java yet: http://forums.ni.com/ni/board/message?board.id=Components&thread.id=5
For command and control: http://zone.ni.com/devzone/cda/tut/p/id/3098