29.3.2 Actions when failures are detected
The following figure shows operation when a ring fault has been detected for a single ring.
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- <Structure of this section>
(1) Master node operation
A fault is determined to have occurred when health check frames in both directions are not received within the pre-determined time. Switching operation is performed as follows on the master node that detects the fault:
- 1. The VLAN status of the ring for data transfer is changed.
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The ring VLAN status for the secondary port is changed from Blocking to Forwarding. The ring VLAN status when a fault is detected is changed as shown in the following table.
Table 29-2: VLAN status for transferring data when a failure is detected Ring port
Before (normal)
After (fault)
Primary port
Forwarding
Forwarding
Secondary port
Blocking
Forwarding
- 2. Flush control frames are sent.
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Flush control frames are sent from the primary port and secondary port of the master node.
- 3. The MAC address table is cleared.
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Clears MAC address table entry. Clearing the MAC address table entries allows paths to be switched quickly.
- 4. The monitoring status is changed.
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When a ring fault is detected, the master node changes from the fault monitoring status to the recovery monitoring status.
(2) Transit node operation
The following operation is performed on a transit node that receives a flush control frame sent from a master node detecting a fault:
- 5. Flush control frames are transferred.
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Any received flush control frames are transferred to the next node.
- 6. The MAC address table is cleared.
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Clears MAC address table entry. Clearing the MAC address table entries allows paths to be switched quickly.