User's Manual

Table Of Contents
271
Users Manual of CS-6306R
26.1.3 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
kinds of packets are 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.
26.1.4 Fast Ethernet Ring Protection Mechanism
26.1.4.1 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 in a certain time (which can be configured), it will
regard the ring network is out of effect. Then the master node removes the blocking of data VLANs on the
secondary port, ages the local MAC address table, and transmits the RING-DOWN-FLUSH-FDB packets to
notify other nodes.
If the master node receives the HEALTH packets at the secondary port that is open to data VLANs, the ring
network is resumed. In this case, the master node immediately blocks data VLANs on the secondary port,
updates the local topology information and reports other nodes to age the MAC address table through
RING-UP-FLUSH-FDB packets.
You can configure related commands on the Hello-time node and the Fail-time node to modify the interval for
the primary port to transmit the HEALTH packets and the time limit for the secondary port to wait for the
HEALTH packets.