Siemens SIMATIC S7-400 Manual page 67

Routing Gateways: MPI - DP - PROFINET
The following figure shows access from MPI to PROFINET via PROFIBUS. CPU 1, for
example 416-3, is the router for subnet 1 and 2; CPU 2 is the router for subnet 2 and 3.
Figure 4-2
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0
Routing gateways: MPI - DP - PROFINET
Communication
4.2 Communication services
4-15