
Glossary
Glossary-7
SIMATIC NET Twisted-Pair and Fiber-Optic Networks
C79000-G8976-C125-02
RJ-45
Connector for data lines also known as the Western plug. Commonly used
connector in telephone and ISDN systems. This connector is also used in LAN
installations in offices.
Router
Active network component that controls data traffic based on the IP address.
Routers have a wide range of filtering and data management functions.
Segment
In triaxial networks, the transceivers connected together via 727-0 LAN cables
and the nodes connected by 727-1 drop cables form a segment.
Several such segments can be connected via repeaters.
When using twisted pair and fiber-optic cables, each subsection forms a
segment.
Segmentation
Disconnection of a faulty segment from an Ethernet network. With this function,
network components such as OLMs, ELMs, ASGEs are capable of limiting faults
to a segment.
Shared LAN
All components in a shared LAN operate at the nominal data rate. Shared LANs
are structured with repeaters/hubs.
Shield impedance
Resistance to alternating current of the cable shield. Shield impedance is a cha-
racteristic of the cable used and is normally specified by the manufacturer.
Signal propagation time
The time required by a data packet to on its way through the network.
Spanning Tree Protocol
Configuration protocol for bridges specified in the IEEE 802.1d standard.
Different ports in the bridges are switched to standby in meshed bridge
structures to prevent data packets from circulating in the network. The result is a
network with a tree structure. The standby ports/connections are available as
redundant connections if a fault develops. Reconfiguration of the network using
the spanning tree protocol can take from several seconds up to a minute and is
therefore not suitable for industrial purposes.
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