You may connect one redundant AS per CPU without redundant communication modules. 
Connection possibilities:
● Single connection of an AS 41xH with one CP each per CPU. Availability is then reduced 
accordingly.
● Single connection of an AS 41xH via an internal Ethernet interface of the CPU. Availability 
is then reduced accordingly.
● Redundant connection of an AS 410H via internal Ethernet interfaces of the CPU
AS 410 on redundant, high availability plant bus
An AS 410 can be connected to the redundant, high availability plant bus without 
communication modules. You can find additional information on this in section "AS 410H on 
redundant, high availability plant bus (Page 74)".
Availability - redundant, high availability plant bus 
The block diagram for a redundant, high availability plant bus with two CPs each in both OS 
servers and additional switches appears as follows:
In this system, one CP 16x3 can fail in each OS server or one CP 443‑1 in each subsystem 
of the AS without this affecting the complete system. The plant bus (bus) is configured 
redundantly and with redundant switches in each case. As a result, a failure of the bus 
component and all components involved (switches) is covered.
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Additional information
● Section "Connecting PC stations to the plant bus (Page 68)"
● Section "Media Redundancy Protocol (Page 59)"
● Section "How to configure a high availability plant bus (Page 117)"
● Documentation 
PCS 7 Released Modules
● Manual 
SIMATIC Net Twisted Pair and Fiber-Optic Networks
● Operating instructions
 SIMATIC NET; Industrial Ethernet Switches SCALANCE X-400
● Manual 
SIMATIC Communication with SIMATIC
High availability solutions in PCS 7
4.3 Solutions for communication
High Availability Process Control Systems (V9.0)
Function Manual, 05/2017, A5E39221836-AA 73