Indu-Sol PROmesh P20, Руководство пользователя

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Device ports and status indicators
PROmesh P20 - User Manual 17

STP
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RSTP

MSTP
Figure 5: PROmesh P20 in a star-shaped network
2.7 Ring structure
Ethernet-based networks make it possible to set up ring structures. These are characterized by each device
being able to forward data in the form of Ethernet packages to the other network devices along at least two
physical paths.
Using this network structure in your PROFINET domain thus makes it possible to establish redundant
availability of all network devices if a connection between two devices of the ring structure should be
interrupted.
The industrial Ethernet switch plays a key role in the implementation of a redundant network structure, by
logically restricting the forwarding of data of all network devices to only one path and switching over to the
alternative forwarding path in the event of an error. Thus unambiguous communication, low netload and
simple media redundancy are all safeguarded simultaneously. Within the scope of the PROFINET standard,
it is recommended to set up ring structures based on the MRP protocol (as per IEC 62439), to identify a
secured interruption of ring structures in the PLC domain, as well as the associated switchover, and react
to it through technical measures.