Operating instructions

Network topologies
2.2 Ring with redundancy manager
Industrial Ethernet SCALANCE X-100 and SCALANCE X-200 Product Line
Operating instructions, 09/2006, A5E00349864 Release 7
2-7
To increase availability, optical or electrical bus topologies made up of SCALANCE X-200
switches with a SCALANCE X-200IRT, SCALANCE X414-3E, OSM Version 2, or ESM
Version 2 configured as a redundancy manager can be closed to form a ring. The
SCALANCE X-200 switches are first connected over their ring ports to form a bus. The two
ends of the bus are closed to form a ring by a switch operating in the redundancy manager
mode. Devices of the SCALANCE X-200 IRT, SCALANCE X400 product families, or OSMs /
ESMs can be used as redundancy managers. When a switch is used as the redundancy
manager, the ring ports are isolated from each other if the network is operating problem-free.
The SCALANCE X-200IRT, SCALANCE X414-3E, or OSM / ESM operating in the
redundancy manager mode monitors the connected bus over its ring ports and switches the
ring ports through if there is an interruption on the connected bus; in other words, it restores
a functioning bus over this substitute path. Reconfiguration takes place within 0.3 seconds.
As soon as the problem has been eliminated, the original topology is restored; in other
words, the ring ports in the redundancy manager are once again disconnected from each
other.
2.2 Ring with redundancy manager
To increase network availability, optical, electrical, or mixed bus topologies comprising up to
50 switches (SCALANCE X-400, SCALANCE X-200 or OSM/ESM) can be closed to form a
ring.
Functional description
The two ends of the bus are closed to form a ring by a SCALANCE X-200IRT operating as a
redundancy manager. The redundancy function is enabled and disabled by pressing a button
on the front of the device or with the WEB interface (cannot be set by PNIO).
In contrast to the ring ports of the other switches, the ring ports of the redundancy manager
are disconnected when the network is operating problem-free. The SCALANCE X-200IRT
operating in the redundancy manager mode monitors the connected bus over its ring ports
and switches the ring ports through if there is an interruption on the connected bus; in other
words, it restores a functioning bus over this substitute path. Reconfiguration takes place
within 0.3 seconds. As soon as the problem has been eliminated, the original topology is
restored; in other words, the ring ports in the redundancy manager are once again
disconnected from each other.
In a SCALANCE X204IRT, ports 1 and 2 are set as ring ports. In a SCALANCE X202-2IRT,
ports 3 and 4 (optical ports) are set as ring ports. This setting can also be changed with the
WEB interface.
After the RM function has been enabled or after the RM has been switched through, this is
indicated by the RM LED on the housing.
Only one switch can be configured as a redundancy manager in a ring.