Hi, we too have a callmanager and IPCC environment, albeit with a single IPCC. To understand the roles played by each of the components it is a good thing to understand the flow of a call from end to end.
When a caller calls in, the IPCC initially has no visibility of it. The gateway on which the call arrives signals the callmanager subscriber and it's database is referenced. Generally a translation is configured on the callmanager which picks up on the number dialled by the caller (aka DNIS). This is translated to another number (Trigger) which has been configured as associated with a CTI route point. The IPCC has applications, each of which runs a script, and these applications each have one or more of the trigger numbers mentioned in the previous sentence. When the callmanager receives a call that is translated to a trigger number (CTI route point) the call is handed to the IPCC and the script is run. This all happens very quickly, and what the caller hears depends upon what is written in the script.
So, in summary and to answer your questions,
The IPCC provides script based interactivity for calls handled by the callmanager.
The callmanager is responsible for the taking and translation of the call, and any transfers etc.
The scripts can be very simple or very complex and can provide such things as IVR, voice recognition(in tandem with other servers), email and http interaction.
The callmanager directs the calls based on which IPCC is configured with an application bearing the trigger number
in essence the IPCC is a bolt-on for the callmanager, as all call processing is done by the callmanager and the IPCC deals with script based interaction with the caller if called upon to do so. Not all calls handled by a callmangager need involve ipcc
IPCC cannot function standalone, as good as it may be.
I hope this helps, it certainly did when i was trying to get a handle on it.
