User's Manual

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Users Manual of CS-6306R
Chapter 24. FlexLinkLite Configuration
FlexLinkLite Configuration 24.1
24.1.1 FlexLinkLite Overview
FlexLinkLite is used in a network environment to easily construct two uplink links, which back up each other. If
STP is not enabled in this network environment, FlexLinkLite can avoid the loop and conduct fast switchover
when a link is out of effect.
Figure 1: FlexLinkLite-enabled network
FlexLinkLite includes a pair of ports that back up each other. As shown in figure 1, FlexLinkLite is enabled on
switch S2, and G5/1 and G5/2 are two ports that back up each other, the former being an active port while the
latter being a backup port. In normal case, the active port forwards data and the backup port blocks data so as
to avoid data loopback. If the active port's link is out of effect, the backup port will immediately begin to
forward data.
A pair of ports, which back up each other, can be two physical ports, or a physical port and an aggregation
port, or two aggregation ports. The port on which FlexLinkLite is set cannot be used for STP calculation or
EAPS settings.
In case the links of two ports are up, the preempt mode is used to select which port to forward data.
FlexLinkLite only supports the preempt based on the preset role. As shown in figure 1, when a link is out of
effect and the preempt is set, port G0/1 will replace port G0/2 to forward data and port G5/2 will block data.
FlexLinkLite also has a topology change notification mechanism. As shown in figure 1, port G0/2 of switch S2
replaces port G0/1 to start forwarding data; S2 sends the TCN packets positively, and S1, after receiving
these TCN packets, immediately clears the MAC addresses that are learned by the downlink ports, G0/10 and
G0/11, and switches the downlink data flow rapidly to the correct link. In general, the TCN mechanism can
assure the successful switchover of the two-way flow in 50ms.