Operation Manual – Smart Link-Monitor LinkH3C S3100 Series Ethernet Switches Chapter 1 Smart Link Configuration1-31.1.2 Operating Mechanism of Smart LinkBLOCKSwitch A Switch BEth1/0/1 Eth1/0/2Switch C Switch DSwitch EEth1/0/1Eth1/0/2Eth1/0/3Eth1/0/1Eth1/0/2Eth1/0/11 Eth1/0/12Figure 1-2 Network diagram of Smart Link operating mechanismAs shown in Figure 1-2, Ethernet1/0/1 on Switch A is active and Ethernet1/0/2 onSwitch A is blocked. When the link connected to Ethernet1/0/1 fails, Ethernet1/0/1 isblocked automatically, and the state of Ethernet1/0/2 turns to active state.z When link switching occurs in the Smart Link group, MAC forwarding entries andARP entries of each device in the network may be out of date. In order toguarantee correct packet transmission, you must enable the Smart Link device tosend flush messages to notify the other devices in the network to refresh their ownMAC forwarding entries and ARP entries. In this case, all the uplink devices mustbe capable of identifying flush messages from the Smart Link group and refreshingMAC forwarding entries and ARP entries.z On a Smart Link–enabled device, if a port is blocked due to link failure, the portremains blocked after the link recovers from the failure, and does not preempt thetraffic resource. Therefore, the traffic stays stable. The port does not come into theforwarding state until the next link switching.
