User's Manual

Table Of Contents
284
Users Manual of CS-6306R
RING-UP-FLUSH-FDB packets.
As shown in the following figure, the master node, S4, transmits the HELLO packets periodically. If the
loopback has no troubles, the HELLO packets will arrive at the secondary port of the master node, and the
master node will block data forwarding of the data VLAN that the secondary port belongs to, preventing the
loopback from happening.
Figure 3: Polling
Remarks:
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.
27.1.4.2 Notification of Invalid Link of Transit Node
Link state notification is a mechanism faster than the polling mechanism to change the ring topology:
After the transit port of the transit node is out of effect, the LINK-DOWN packet will be immediately transmitted
by the other transit port to notify other nodes. In normal case, the packet passes through other transit nodes
and finally arrives at one port of the master node.
After the master node receives the LINK-DOWN packet, it thinks that the ring network is invalid. In this case,
the master node removes the blocking of data VLANs on its secondaryport, ages the local MAC address table,
transmits the RING-DOWN-FLUSH-FDB packet and notifies other nodes. As shown in the following figure,
trouble occurs on the link between node S3 and node S6. After node S3 and node S6 detect that trouble has
already occurred on the link, they block the ports that the troubled link corresponds to and transmit the
LINK-DOWN packets respectively from the other port; when the master node receives the LINK-DOWN
packets, holds that the trouble occurs on the loopback, and decides not to wait for the fail-time any more.