Operating instructions

Glossary
Industrial Ethernet SCALANCE X-100 and SCALANCE X-200 Product Line
Operating instructions, 09/2006, A5E00349864 Release 7
Glossary-3
Multimode
In multimode transmission, the pulse is transferred using many modes (waves) that travel
along curved paths or are reflected within the core. Attenuation is mainly caused by physical
absorption and dispersion as well as by mechanical bending. The amount of attenuation
depends among other things on the wavelength of the input light. Multimode fiber-optic
cables have an outer diameter of 125 µm and 50 or 62.5 µm core diameter. Due to the larger
core diameter the pulse edges degrade more than in single mode transmission resulting in
shorter transmission distances.
OSM
Optical Switching Module – SIMATIC NET Ethernet switch with optical ports.
Passive listening
Support of Rapid Spanning Tree Topology Change frames. When an RSTP topology change
frame is received, the MAC address table is deleted.
PCF
Polymer Cladded Fiber
Optical fiber that can be assembled in the field and whose core is made of glass and jacket
made of plastic.
POF
Plastic Optical Fiber
Optical fiber that can be assembled in the field and whose core and jacket are made of
plastic.
Reconfiguration time
The time required to restore a functional configuration if a device fails or a network cable is
interrupted.
Redundancy manager
Network node in a ring topology that does not forward any frames between its ring ports if
there are functioning connections between all other nodes. As soon as a connection
between two nodes is interrupted, the redundancy manager forwards frames so that there is
an intact connection between all nodes.
Ring port
Two ports in a switch via which it is connected with other switches to form a ring. One switch
must be configured as the redundancy manager in the ring. This sends test frames via the
ring ports that are forwarded by all the ring ports of the other switches in the ring. This makes
sure that the ring does not have any interruptions.