Relation between PI and BPM?

Hi Experts,

As far as i know PI is the middleware between two incompatible systems, like MDM<->PI<->ECC. Could someone through some light on

1. What is the role of BPM in PI?

2. What is the difference between ccBPM and BPM?

3. Does BPM always co-exists with PI or vice-verse?

Thanks in advance.

regards

mohan