Ring Structure - Siemens SIMATIC NET System Manual

2.2.4

Ring structure

"Ring"
If the ends of a bus are connected via an additional connection, this results in a ring
structure. The switches connected together in a ring do not need to be interconnected only
with FO cables or only electrical cables. A mixed electrical-optical ring is also permitted.
A special redundancy mechanism ensures that the ring structure remains a logical bus in
normal situations and prevents frames from circulating. If a section of the ring fails, the
mechanism quickly makes a substitute path available in the ring: The message now travels
the long way round via the intact network section instead of over the direct path that is now
interrupted and reaches its recipient via this detour. The network does not fall apart into two
segments.
Figure 2-5 Redundant 10 Gbps ring structure and 10 Gbps backbone with SCALANCE XR-500
● The effects of a network component malfunction are thus restricted to the failed
component and to the end devices connected to the component. If a ring section is
interrupted by a cable break, for example, communication continues without any
disruption.
The reconfiguration time is faster here than in the office world and meets the requirements of
the automation world.
Industrial Ethernet
System Manual, 09/2019, C79000-G8976-C242-10
Network structures and network configuration
2.2 Network structures
79