1-11 Monitor Link ConfigurationWhen configuring monitor link, go to these sections for information you are interested in:z Overviewz Configuring Monitor Linkz Displaying and Maintaining Monitor Linkz Monitor Link Configuration ExampleOverviewMonitor link is a port collaboration function used to enable a device to be aware of the up/down statechange of the ports on an indirectly connected link. Monitor link is usually used in conjunction withLayer-2 topology protocols. The idea is to adapt the up/down state of downlink ports to the up/downstate of uplink ports, triggering link switchover on the downlink device in time.TerminologyMonitor link groupA monitor link group is a set of uplink ports and downlink ports. For the purpose of monitor link, uplinkports refer to the monitored ports while downlink ports refer to the ports adapted to the up/down state ofthe monitored ports. A port can be assigned to only one monitor link group. Both Layer-2 Ethernet portsand Layer-2 aggregate interfaces can be assigned to a monitor link group.UplinkThe uplink is the link monitored by the monitor link group. The monitor link group is down when thegroup has no uplink ports or all uplink ports are down. The monitor link group is up when any uplink portis up.DownlinkThe downlink is the state-adaptive link in the monitor link group. The state of the downlink ports isalways consistent with the up/down state of the monitor link group.How Monitor Link WorksA monitor link group works independently of other monitor link groups. When a monitor link groupcontains no uplink ports or all its uplink ports go down, the monitor link group goes down and forces alldownlink ports down at the same time. When any uplink port goes up, the monitor link group goes upand brings up all the downlink ports.
