Redundantly Coupled Networks - Siemens SIMATIC NET System Manual

Examples of applications

3.2 Redundantly coupled networks

Benefits
● Lower network loads because broadcast frames are only sent to the nodes of the
corresponding VLAN
● The data traffic can be prioritized in accordance with the standard IEEE 802.1Q.
● Segmentation can be a security function when routing between segments is restricted, for
example, through firewalls.
3.2 Redundantly coupled networks
Task
In a production company the enterprise network is to be connected reliably with the
production network. Faults or the failure of a connecting cable should not have any influence
on the data traffic. In addition, the production network is to be protected against unauthorized
accesses from the enterprise network.
Solution
To achieve a sufficiently high level of reliability, a redundant Layer 3 coupling is realized. The
firewall routers
and a virtual MAC address are assigned to these two devices. One of the routers is active as
a master router. If this device fails, the other router takes over the function of the master
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and are combined with VRRP into a logical router. A virtual IP address
System Manual, 09/2019, C79000-G8976-C242-10
Industrial Ethernet