H3C Technologies H3C S3100 Series Switches - Manual (Page 956)

2-2
How Monitor Link Works
Figure 2-2 Network diagram for a Monitor Link group implementation
BLOCK
Switch A Switch B
Eth1/0/1
Eth1/0/2
Switch C Switch D
Switch E
Eth1/0/1
Eth1/0/2
Eth1/0/3
Eth1/0/1
Eth1/0/2
Eth1/0/11 Eth1/0/12
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 Ethernet1/0/1 is the uplink port, while
Ethernet1/0/2 and Ethernet1/0/3 are the downlink ports. Switch A is configured with a Smart Link group,
where Ethernet1/0/1 is the master port and Ethernet1/0/2 is the slave port.
z If Switch C is not configured with Monitor Link group, when the link for the uplink port Ethernet1/0/1
on Switch C fails, the links in the Smart Link group are not switched because the link for the master
port Ethernet1/0/1 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 Ethernet1/0/1.
z If Switch C is configured with Monitor Link group and Monitor Link group detects that the link for the
uplink port Ethernet1/0/1 fails, all the downlink ports in the group are shut down; therefore,
Ethernet1/0/3 on Switch C is blocked. Now, Smart Link group configured on Switch A detects that a
link fault occurs on the master port Ethernet1/0/1. Then, Smart Link immediately activates the slave
port Ethernet1/0/2 so that traffic is switched to the backup link.
z Currently, member ports of a Monitor Link group cannot be dynamic link aggregation groups.
z 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.
Configuring Monitor Link