3Com Switch 7754, Configuration Manual

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906 C
HAPTER
82: RRPP C
ONFIGURATION
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Fail timer: Defines the timeout time for the secondary port of the master node
to receive health detection packets. The value of Fail timer must be greater
than or equal to three times the Hello timer value.
RRPP Message Type The following table describes RRPP message types.
Basic Principles of RRPP Link DOWN notification mechanism
When detecting a port in the RRPP domain is down, a transit node sends the LINK
DOWN packet immediately to the master node. After receiving the LINK DOWN
packet, the master node unblocks the data VLAN of the secondary port, and sends
the Common Flush packet to tell all transit nodes to refresh their respective MAC
address FDB and ARP table.
Polling mechanism
The primary port of the master node periodically sends the health detection packet
in a control VLAN.
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If the secondary port of the master node receives the health detection packet,
this indicates that the ring link is complete, and the master node will keep the
secondary port blocked.
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If the secondary port of the master node fails to receive the health detection
packet within the predefined timeout time, this indicates that a failure has
occurred to the ring link. In this case, the master node unblocks the data
VLANs on the secondary port, and sends the Common Flush packet to tell all
transit nodes to refresh their respective MAC address FDB and ARP table.
Ring recovery
The master node may detect that the ring has recovered a period time after the
RRPP domain port on a transit node becomes UP again. In this period, a temporary
data loop may occur in data VLANs, which can cause broadcast storm.
Table 705 RRPP messages
Message Description
HEALTH (HELLO)t The master node sends the HELLO message to detect whether the
ring network is complete.
LINK DOWN A transit node sends this message to notify the master node that a
port is DOWN and the physical ring is disconnected.
COMMON- FLUSH-FDB The master node sends this message to tell all the transit nodes to
refresh their respective MAC address FDB.
COMPLETE- FLUSH-FDB The master node sends this message to tell all the transit nodes to
refresh their respective MAC address FDB and unblock the ports in
the blocked data VLANs.
EDGE-HELLO This message is generated by the edge node of a subring and
received by the assistant edge node in the same subring. The
subring uses this message to check the integrity of the primary ring
in the home domain.
MAJOR-FAULT This message is generated by the assistant edge node of a subring. If
the assistant edge node does not receive the EDGE-HELLO from the
edge node within the specified period, it reports to the edge node
that a fault exists in the primary ring of the home domain.