There's what we call the blunt-object (or silo'd or stove-piped) approach, which is, unfortunately, what seems to be the most common approach. In this approach CMMI is implemented with the grace and finesse of a heavy, blunt object at the end of a long lever -- impacting development organizations and project managers' collective craniums.
And then, there's the reality-based approach. In which, processes are implemented in such a way that project personnel may not even know it's happening. Can you guess which one we advocate?
The blunt-object approach resembles what many process improvement experts call "process silos", or "stove pipes". This approach is also often implemented *to* a development team *by* some external process entity with brute force and very extreme prejudice.
So, not only does the blunt approach employ some very unsavory techniques, subjecting its royal subjects to cruel and unusual process punishment, it also (in its design) is characterized by a "look and feel" of a process where each process is in its own vacuum, without any connection to other processes (or to reality, for that matter), and where the practices of the processes are somehow expected to be performed serially, from one to the next, in the absence of any other project context.