When the RPC runtime detects the cancel, it forwards it to the server and the cancel is posted against the server's call executor thread executing your manager routine. So, if your server manager ignores it, the client waits until the call returns. Full DCE for sun-solaris is supplied by transarc. I've setup my first cell in half a day including software installation from a tape drive. Difficulties in using and setting up DCE come from lack of training.
People tend to think that everything in the computer industry has to be easy.
Distributed applications are inherently complex. DCE provides an enterprise-level unified way of developing and managing distributed applications. If one wants to manage different security services, different directory services, learn and train for different transport mechanisms, than why bother with DCE one may ask. The bottom line is that we are in very competitive world where all company executives want to reduce software development and management costs. The natural way to acheive that is by unifying the software architecture and services.