3Com WX3000 operation manual Configuring Smart Link, Operating Mechanism of Smart Link

Operating Mechanism of Smart Link

Figure 1-2Network diagram of Smart Link operating mechanism

	GE 1/0/11	GE1/0/12
	Switch E
Switch C	GE1 /0/1	GE 1/0/1	Switch D
GE 1/0 /3	GE1 /0/2	GE 1/0/2	GE1/0/3

GE 1/0 /1BLOCK

GE1 /0/2

Switch A Switch B

As shown in Figure 1-2, GigabitEthernet 1/0/1 on Switch A is active and GigabitEthernet 1/0/2 on Switch A is blocked. When the link connected to GigabitEthernet 1/0/1 fails, GigabitEthernet 1/0/1 is blocked automatically, and the state of GigabitEthernet 1/0/2 turns to active state.

z

z

When link switching occurs in the Smart Link group, MAC forwarding entries and ARP entries of each device in the network may be out of date.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 the network to refresh their own MAC forwarding entries and ARP entries. In this case, all the uplink devices must be capable of identifying flush messages from the Smart Link group and refreshing MAC forwarding entries and ARP entries.

On a Smart Link–enabled device, if a port is blocked due to link failure, the port remains blocked after the link recovers from the failure, and does not preempt the traffic resource. Therefore, the traffic stays stable. The port does not come into the forwarding state until the next link switching.

Configuring Smart Link

Before configuring a member port of a Smart Link group, you must:

zDisable the port to avoid loops, thus preventing broadcast storm.

zDisable STP on the port.

After completing the configuration, you need to enable the Ethernet ports disabled before configuring the Smart Link group.

Configuration Task List

Complete the following tasks to configure Smart Link:

1-3