Don't know whether this is helpful, but you can trigger Catalyst via telnet commands or http:// commands.
http://x.x.x.x:8080/commands/?RunPreset=1
Where x.x.x.x is the IP address of the machine you wish to trigger.
Telnet:
Start a telnet connection and...
GET /commands/?RunPreset=2 HTTP/1.0
I guess the advantage of using UDP is 'connectionless' comms, but TCP/IP might work for your application.
Hugh