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22.1.3 MRPP Protocol Operation System
1. Link Down Alarm system
When transfer node finds themselves belonging to MRPP ring port Down, it sends
link Down packet to primary node immediately. The primary node receives link down
packet and immediately releases block state of secondary port, and sends
LINK-DOWN-FLUSH-FDB packet to inform all of transfer nodes, refreshing own MAC
address forward list.
2. Poll System
The primary port of primary node sends Hello packet to its neighbors timely
according to configured Hello-timer.
If the ring is health, the secondary port of primary node receives health detect packet,
and the primary node keeps secondary port.
If the ring is break, the secondary port of primary node can’t receive health detect
packet when timer is over time. The primary releases the secondary port block state, and
sends LINK-DOWN-FLUSH_FDB packet to inform all of transfer nodes, to refresh own
MAC address forward list.
3. Ring Restore
After the primary node occur ring fail, if the secondary port receives Hello packet
Packet Type
Explanation
Hello packet (Health examine
packet) Hello
The primary port of primary node evokes to detect
ring, if the secondary port of primary node can
receive Hello packet in configured overtime, so the
ring is normal.
LINK-DOWN (link Down event
packet)
After transfer node detects Down event on port,
immediately sends LINK-DOWN packet to primary
node, and inform primary node ring to fail.
LINK-DOWN-FLUSH_FDB packet
After primary node detects ring failure or receives
LINK-DOWN packet, open blocked secondary port,
and then uses two ports to send the packet, to
inform each transfer node to refresh own MAC
address.
LINK-UP-FLUSH_FDB packet
After primary detects ring failure to restore normal,
and uses packet from primary port, and informs
each transfer node to refresh own MAC address.
