H3C S5120-EI Series - Configuring Monitor Link; Monitor Link Overview; Terminology

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Configuring Monitor Link
Monitor Link overview
Monitor Link is a port collaboration function. Monitor Link usually works together with Layer 2 topology
protocols. The idea is to monitor the states of uplink ports and adapt the up/down state of downlink ports
to the up/down state of uplink ports, triggering link switchover on the downstream device in time, as
shown in Figure 26.
Figure 26 Monitor Link application sc
enario
Terminology
Monitor link group
A monitor link group is a set of uplink and downlink ports. A port can belong to only one monitor link
group. As shown in Figure 26, por
ts Port1 and Port2 of Device B and those of Device D each form a
monitor link group. Port1 on both devices are uplink ports, and Port2 on both devices are downlink ports.
Uplink/Downlink ports
Uplink port and downlink port are two port roles in monitor link groups:
• Uplink ports are the monitored ports. The state of a monitor link group adapts to that of its member
uplink ports. When a monitor link group contains no uplink port or when all the uplink ports are
down, the monitor link group becomes down. As long as one member uplink port is up, the monitor
link group stays up.
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