CPU with integrated PROFIBUS-DP — what you're getting
The 6ES7413-2XG02-0AB0 is a SIMATIC S7-400 CPU 413-2 DP central processing unit carrying 72 KB of working memory, an integrated multi-point MPI interface, and a PROFIBUS-DP interface on-board. This is the CPU that sits in the rack and runs the logic for a mid-sized S7-400 system — the DP port lets it talk directly to remote I/O, drives, or other DP slaves without an extra communications processor. The 72 KB working memory is enough for a moderate control program with a few hundred I/O points; if your application has grown beyond that, you'd be looking at a 414 or 416 CPU.
What the interfaces mean for integration
The MPI interface is the standard Siemens multi-point connection — used for programming, HMI communication, and simple peer-to-peer between S7-400 CPUs. The PROFIBUS-DP interface is the fieldbus side: it handles the deterministic cyclic data exchange with remote I/O racks, drives, and valve islands. If you're replacing a failed CPU in an existing line, verify that the PROFIBUS address and baud rate are set to match the old unit — the DP interface is fixed at 12 Mbit/s max, and the MPI port runs at 187.5 kbit/s by default. Both ports are electrically isolated from the backplane, which helps with ground-loop noise on long DP runs.