1-3z Uplink traffic-triggered MAC address learning, where update is triggered by uplink traffic. Thismechanism is applicable to environments with devices not supporting smart link, including devicesof other vendors’.z Flush update where a Smart Link-enabled device updates its information by transmitting flushmessages over the backup link to its upstream devices. This mechanism requires the upstreamdevices to be capable of recognizing smart link flush messages to update its MAC addressforwarding entries and ARP/ND entries.To keep traffic forwarding stable, the master port that has been blocked due to link failure does not takeover immediately upon its recovery. Instead, link switchover will occur at next link switchover.Role preemption mechanismAs shown in Figure 1-1, the link on GE1/0/1 of Device C is the active link, and the link on GE1/0/2 ofDevice C is the standby link. Once GE1/0/1 fails, GE1/0/2 takes over to forward traffic. During thisperiod, if the smart link group is configured with role preemption, GE1/0/1 takes over to forward traffic assoon as it recovers.Load sharing mechanismA ring network may carry traffic of multiple VLANs. Smart link can forward traffic of different VLANs indifferent smart link groups, thus implementing load sharing.To implement load sharing, you can assign a port to multiple smart link groups (each configured withdifferent protected VLANs), making sure that the state of the port is different in these smart link groups.In this way, traffic of different VLANs can be forwarded along different paths.You can configure protected VLANs for a smart link group by referencing MSTIs.Configuring a Smart Link DeviceTo use Smart Link on a device, you must configure the device with a smart link group and transmitcontrol VLAN for flush message transmission. Device C and Device E in Figure 1-1 are two examples ofSmart Link devices.Configuration Prerequisitesz Before configuring a port as a smart link group member, shut down the port to prevent loops. Youcan bring up the port only after completing the smart link group configuration.z Disable STP and RRPP on the ports you want to add to the smart link group, and make sure thatthe ports are not member ports of any aggregation group.Configuring a Smart Link DeviceFollow these steps to configure a smart link device:To do… Use the command… RemarksEnter system view system-view —Create a smart link group and entersmart link group view smart-link group group-id Required
