3Com WX3000 How Monitor Link Works, 2Network diagram for a Monitor Link group implementation

How Monitor Link Works

Figure 2-2Network diagram for a Monitor Link group implementation

	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 2-2, the devices Switch C and Switch D are connected to the uplink device Switch E. Switch C is configured with a Monitor Link group, where GigabitEthernet 1/0/1 is the uplink port, while GigabitEthernet 1/0/2 and GigabitEthernet 1/0/3 are the downlink ports. Switch A is configured with a Smart Link group, where GigabitEthernet 1/0/1 is the master port and GigabitEthernet 1/0/2 is the slave port.

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If Switch C is not configured with Monitor Link group, when the link for the uplink port GigabitEthernet 1/0/1 on Switch C fails, the links in the Smart Link group are not switched because the link for the master port GigabitEthernet 1/0/1 of Switch A configured with Smart Link group operates normally. Actually, however, the traffic on Switch A cannot be up-linked to Switch E through the link of GigabitEthernet 1/0/1.

If Switch C is configured with Monitor Link group and Monitor Link group detects that the link for the uplink port GigabitEthernet 1/0/1 fails, all the downlink ports in the group are shut down; therefore, GigabitEthernet 1/0/3 on Switch C is blocked. Now, Smart Link group configured on Switch A detects that a link fault occurs on the master port GigabitEthernet 1/0/1. Then, Smart Link immediately activates the slave port GigabitEthernet 1/0/2 so that traffic is switched to the backup link.

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Currently, member ports of a Monitor Link group cannot be dynamic link aggregation groups.

If the uplink or downlink port in the Monitor Link group is a link aggregation group, you cannot directly delete this aggregation group or change this aggregation group into a dynamic aggregation group. To delete this aggregation group, you must first unbind this aggregation group from the Monitor Link.

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