1-3Operating Mechanism of Smart LinkFigure 1-2 Network diagram of Smart Link operating mechanismBLOCKSwitch A Switch BGE 1/0 /1GE1 /0/2Switch C Switch DSwitch EGE1 /0/1GE1 /0/2GE 1/0 /3GE 1/0/1GE 1/0/2 GE1/0/3GE 1/0/11 GE1/0/12As shown in Figure 1-2, GigabitEthernet 1/0/1 on Switch A is active and GigabitEthernet 1/0/2 on SwitchA is blocked. When the link connected to GigabitEthernet 1/0/1 fails, GigabitEthernet 1/0/1 is blockedautomatically, and the state of GigabitEthernet 1/0/2 turns to active state.z When link switching occurs in the Smart Link group, MAC forwarding entries and ARP entries ofeach device in the network may be out of date. In order to guarantee correct packet transmission,you must enable the Smart Link device to send flush messages to notify the other devices in thenetwork to refresh their own MAC forwarding entries and ARP entries. In this case, all the uplinkdevices must be 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 port remains blockedafter the link recovers from the failure, and does not preempt the traffic resource. Therefore, thetraffic stays stable. The port does not come into the forwarding state until the next link switching.Configuring Smart LinkBefore configuring a member port of a Smart Link group, you must:z Disable the port to avoid loops, thus preventing broadcast storm.z Disable STP on the port.After completing the configuration, you need to enable the Ethernet ports disabled before configuringthe Smart Link group.Configuration Task ListComplete the following tasks to configure Smart Link:
