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(8) When multi-faults occur within a network
When multiple faults occur between different nodes in the same ring (a multi-fault),
because the master node was already performing fault detection for the first fault, the
second and subsequent faults are not detected. Also, because health check frames sent by
the master node cannot be received until recovery from the last fault in a multi-fault
restoration detection situation occurs, recovery cannot be detected. As a result,
communication might be temporarily impossible for multi-faults when a partial fault is
restored (when a fault remains for the ring).
Note that when the multi-fault monitoring functionality is applied, multi-faults might be able
to be detected, depending on the combination of faults. For details about the multi-fault
monitoring functionality, see 20.5 Multi-fault monitoring functionality for the Ring Protocol.
(9) Sending and receiving flush control frames when the master node switch restarts
When flush control frames cannot be received on neighboring transit nodes, and the
sending count for flush control frames from the master node is controlled, reception might
be possible. Also, to shorten the time to cut communication due to flush control frames not
yet received, shorten the reception hold time for flush control frames sent by the transit
node (initial value:10 seconds).
(10) Timing for starting monitoring for the multi-fault monitoring functionality
After the multi-fault monitoring functionality is applied to a shared node, multi-fault
monitoring is started when the first multi-fault monitoring frame sent from the opposing
shared node is received. As such, when the multi-fault monitoring functionality is set and a
fault occurs for a ring network, multi-fault monitoring cannot be started. Set the multi-fault
monitoring functionality when the status of the ring network is normal.
(11) Communication during partial multi-fault recovery
Because the master node does not detect ring restoration during partial multi-fault recovery,
the transit node ring port is logically blocked until the reception hold time
(forwarding-shift-time) for flush control frames elapses. To clear the logical block status,
either shorten the reception hold time for flush control frames (initial value:10 seconds), or
recover remaining link faults to have the master node detect ring restoration. Also, when
setting the reception hold time for flush control frames, set a value greater than the sending
interval for multi-fault monitoring frames for the master node (using the
multi-fault-detection interval
loops might occur temporarily.
(12) How to shut down link aggregation specified as the ring port
When nodes in a ring network are connected via link aggregation (static mode or LACP
mode), make sure to shut down all physical ports belonging to the channel group by using
the
shutdown
aggregation by using the
If you bring up the channel group using the
sure to shut down all physical ports belonging to the channel group by using the
configuration command.
configuration command before shutting down the channel group of the link
shutdown
configuration command.
20 Description of the Ring Protocol
configuration command). When a small value is set,
no shutdown
configuration command, make
shutdown
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