HMS Networks Anybus CompactCom 40 Network Manual page 42

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Anybus CompactCom 40 - PROFINET IRT Transparent Media Reduncancy Protocol (MRP)
Ethernet
7. Media Reduncancy Protocol (MRP)
7.1. General
Media Redundancy Protocol (MRP) is a PROFINET specific ring protocol ensuring redundancy in the network,
which can significantly decrease network downtime. It is a token based ring protocol with a master-slave
hierarchy.
All the nodes in the PROFINET network part of the ring are connected using ring topology (that is, the last node
is connected directly to the first node). If, at any point, the connection between two nodes would break, the data
will flow the other way instead, guaranteeing that data can be sent to/from the IO Controller to the IO Device(s).
The self-healing time is approximately 200 ms.
The Media Redundancy Master (MRM) is responsible for checking the functional capability of the ring network,
by sending out cyclic tokens. The Media Redundancy Clients (MRC) basically work as switches that pass on
the tokens. The Anybus CompactCom supports acting as a Media Redundancy Client (MRC). It also supports
propagating link change to the Media Redundancy Master.
If port 2 of the device is inactivated in the Ethernet Host Object (F9h), support for MRP is removed. See Ethernet
Host Object (F9h) (page 132) , instance attribute #13, for more information.
7.2. GSDML Entries
MRP functionality is enabled by default in the GSD file. The settings for MRP are located at the Device Access
Point (DAP). within the <InterfaceSubmoduleItem ...>. The Anybus CompactCom is defined as "Client"
with the keyword <MediaRedundancy SupportedRole="Client"/>.
For each physical port there are two keywords in the <PortSubmoduleItem ...> section
<PortSubmoduleItem ... SupportsRingportConfig="true"IsDefaultRingport="true"
... />. These are set to "true" by default. To disable MRP, these two shall be set to"false".
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