Digisol DG-FS4528P, Руководство по управлению

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C
HAPTER
37 | EAPS Commands
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When the master node receives this “link down” control frame, the master
node moves from the “normal” state to the ring-fault state and unblocks its
secondary port. The master node also flushes its bridging table, and sends
a control frame to all other ring nodes, instructing them to flush their
bridging tables as well. Immediately after flushing its bridging table, each
node begins learning the new topology.
Ring Polling – The master node sends a health-check frame on the
Control VLAN at a user-configurable interval. If the ring is complete, the
health-check frame will be received on its secondary port, and the master
node resets its fail-period timer and continues normal operation.
If the master node does not receive the health-check frame before the fail-
period timer expires, the master node moves from normal state to “ring-
fault” state and unblocks its secondary port. The master node flushes its
bridging table and sends a control frame to all other nodes, instructing
them to also flush their bridging tables. Immediately after flushing its
bridge table, each node starts learning the new topology. This ring polling
mechanism provides a backup in the event that the Link Down Alert frame
should get lost for some unforeseen reason.
Ring Restoration – The master node continues sending periodic health-
check frames out its primary port even when operating in the ring-fault
state. Once the ring is restored, the next health-check frame will be
received on the master node's secondary port. This will cause the master
node to transition back to the normal state, logically block non-control
frames on the secondary port, flush its own bridge table, and send a
control frame to the transit nodes, instructing them to flush their bridging
tables and re-learn the topology.
During the time between the transit node detecting that its link is restored
and the master node detecting that the ring is restored, the secondary port
of the master node is still open °V creating the possibility of a temporary
loop in the topology. To prevent this, the transit node will place all the
protected VLANs transiting the newly restored port into a temporary
blocked state, remember which port has been temporarily blocked, and
then transition into the “pre-forwarding” state. When the transit node in
the “pre-forwarding” state receives a control frame instructing it to flush its
bridging table, it will flush the bridging table, unblock the previously
blocked protected VLANs on the newly restored port, and transition to the
“normal” state.
Multiple EAPS Domains – An EAPS-enabled switch can be part of more
than one ring. Hence, an EAPS-enabled switch can belong to more than
one EAPS Domain at the same time. Each EAPS Domain on an switch
requires a separate instance of the EAPS protocol on that same switch, one
instance per EAPS-protected ring.
There can also be more than one EAPS domain running on the same ring at
the same time. Each EAPS Domain has its own unique master node and its
own set of protected VLANs. This facilitates reuse of the ring's bandwidth.