User's Manual

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Note:
The data VLAN can be used for normal L2/L3 communication. For example, you can establish
a VLAN port corresponding to data VLAN and configure dynamic routing protocols.
41.2.4 Aging of the MAC Address Table
The Ethernet ring protection protocol can transmit data packets to the correct link by controlling the aging of
the switch’s MAC address table when the topology changes. In general, the time for a MAC address to age in
the MAC address table is 300 seconds. The ring protection protocol can control the aging of the MAC address
table in a short time.
41.2.5 Symbol of a Complete Ring Network
Both the master node and the transit node can show whether the current ring network is complete through the
state symbol “COMPLETE”. On the master node, only when all links of the ring network are normal, the primary
port is in the forwarding state and the secondary port is in blocking state showing the "COMPLETE” symbol;
on the transit node, its two transit ports are in the forwarding state showing the “COMPLETE” symbol.
The state symbol of the ring network helps user to judge the topology state of the current network.
41.3 Types of EAPS Packets
The EAPS packets can be classified into the following types, as shown in table 1.1.
Table 1.1 Types of EAPS packets
Type of the packet Remarks
Loopback detection
（HEALTH）
It is transmitted by the master node to detect whether the topology
of the ring network is complete.
LINK-DOWN Indicates that link interruption happens in the ring. This kind of
packet is transmitted by the transit node.
RING-DOWN-FLUSH-FDB It is transmitted by the master node after interruption of the ring
network is detected and the packets show the MAC address aging
table of the transit node.
RING-UP-FLUSH-FDB It is transmitted by the master node after interruption of the ring
network is resumed and the packets show the MAC address aging
table of the transit node.
41.4 Fast Ethernet Ring Protection Mechanism
41.4.1 Ring Detection and Control of Master Node
The master node transmits the HEALTH packets to the control VLAN through the primary port in a configurable
period. In normal case, the HEALTH packets will pass through all other nodes of the ring network and finally
arrive at the secondary port of the master node.
The secondary port blocks all data VLANs in primitive condition. When receiving the HEALTH packets
continuously, the secondary port keeps blocking data VLANs and blocking the loop. If the secondary port does
not receive the HEALTH packets from the primary port at a certain time (which can be configured), it will regard