GFK-2571A
Chapter 6 Redundant Media
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Sequence for Enabling Media Redundancy
To avoid network loops occurring before the Media Redundancy configuration parameters are
stored, the network must first be set up with the ring broken at one point. Otherwise, packets could
continuously cycle on the network and use up significant network bandwidth. The ring should not be
closed until the Media Redundancy configuration parameters are successfully stored to the Media
Redundancy Manager and the Media Redundancy Manager is operational.
If more than one Media Redundancy Manager is present on the same ring, each PNC module that is
configured as a Media Redundancy Manager will log a fault in its local log and in the RX3i
CPU’s I/O
Fault Table. When the RX3i configuration is cleared, the Media Redundancy configuration
parameters (Media Redundancy Manager or Client) are kept until a new setting is stored. If power is
lost, the Media Redundancy configuration settings are preserved.
Note:
When configuring a Media Redundancy Manager in an open ring, the module may initially
report the ring to be closed. This indication will immediately be followed by a ring open event. This is
expected behavior defined by the MRP specification.
Sequence for Replacing a Media Redundancy Manager
If it is necessary to replace the PNC that is serving as the Media Redundancy Manager, the
replacement module must be set up as a Media Redundancy Manager before adding it to the ring.
Alternatively, the ring must be opened before powering up the new module and adding it to the
network, as described above.
The following procedure can be used to replace a PNC that is operating as Media Redundancy
Manager without disrupting the network.
1. Verify that the ring has no breaks in it, or that the only break involves the Media Redundancy
Manager itself. If the ring is already broken someplace else, the Media Redundancy Manager
must remain operational at all times or connectivity between the remaining devices is not
guaranteed.
2.
Physically disconnect both of the ring’s network connections from the PNC that is serving as the
Media Redundancy Manager.
3. Extract the PNC from the RX3i rack.
4. Using the Machine Edition programmer, make sure the PNC
’s configuration is stored to the RX3i
CPU.
5. Insert the replacement PNC into the RX3i rack.
6. Using the Machine Edition programmer, view the Fault Tables to make sure the PNC is
configured correctly.
7.
Physically reconnect both of the ring’s network connections to the replacement PNC.
