
Glossary
Industrial Ethernet OSM/ESM
86
C79000-Z8976-C068-04
ITP Port
Port with Industrial Twisted Pair (ITP) connector (sub D 9-pin female)
Latency
The latency specifies the taken for packets to pass through the
OSM/ESM. It is assumed that a received packet can be sent on
immediately. The latency does not include the time necessary for the
OSM/ESM to receive a packet.
Link Control
OSMs/ESMs monitor the connected TP/ITP cable segments for short-
circuits or wire breaks using regular link test pulses complying with the
100BASE-TX standard. OSMs/ESMs do not send data to a segment from
which they are not receiving link test pulses. An unused interface is taken
to be a wire break since the device without power cannot send link test
pulses.
OSM
Optical Switching Module. SIMATIC NET Ethernet switch with optical and
electrical ports
Reconfiguration Time
Time required by the OSM/ESM operating in the redundancy manager
(RM) or standby mode to reestablish a functioning configuration if a
device fails or the cable is interrupted.
Redundancy Manager
(RM)
Mode of an OSM or ESM for forming a redundant ring structure. The RM
monitors the OSM or ESM bus connected to it, closes the bus if it detects
and interruption. This reestablishes a functioning bus configuration.
One and only one device can operate in the RM mode in every OSM or
ESM ring.
Signaling Contact
Floating relay contact via which the error states detected by the
OSM/ESM can be signaled.
Standby Sync Port
Port of an OSM/ESM via which the two OSMs or ESMs are connected in
a redundant coupling to inform each other of their operating states.
Store and forward
In this switching method used on the OSM/ESM, the complete packet is
read in before it is passed on by the switch. A packet is only passed on if it
is error-free.
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