Siemens SCALANCE X-300 Manual page 18

Introduction
2.1 Basics of Ethernet switching
Technical options (network topologies)
The IE Switches X-300 simplify the expansion of a network regardless of the network
topology.
You can use an IE Switch X-300 in the following network topologies:
● Linear structure
● Star/tree structure
● Ring with redundancy manager
The maximum cable length is 70 km for single mode gigabit transmission. A mixed topology
consisting of IE Switch X-300 devices and OSMs/ESMs is possible at the electrical ports. A
mixed topology consisting of IE Switch X-300 devices and an OSM via the optical ports is not
possible.
Using an IE Switch X-300 as the redundancy manager in a ring with redundancy manager
provides greater availability. If there is an interruption on the connection between these
switches, the IE Switch X-300 used as redundancy manager acts like a switch and in a very
short time creates a line from the ring. As a result, a functional, end-to-end structure is
restored. For information on this topic, refer to the Configuration Manual "SIMATIC NET -
Industrial Ethernet Switches SCALANCE X-300 SCALANCE X-400."
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Operating Instructions, 10/2010, A5E01113043-10
SCALANCE X-300