Operation Manual – Smart Link-Monitor LinkH3C S3100 Series Ethernet Switches Chapter 2 Monitor Link Configuration2-22.1.1 How Monitor Link WorksBLOCKSwitch 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 2-2 Network diagram for a Monitor Link group implementationAs shown in Figure 2-2, the devices Switch C and Switch D are connected to the uplinkdevice Switch E. Switch C is configured with a Monitor Link group, where Ethernet1/0/1is the uplink port, while Ethernet1/0/2 and Ethernet1/0/3 are the downlink ports. SwitchA is configured with a Smart Link group, where Ethernet1/0/1 is the master port andEthernet1/0/2 is the slave port.z If Switch C is not configured with Monitor Link group, when the link for the uplinkport Ethernet1/0/1 on Switch C fails, the links in the Smart Link group are notswitched because the link for the master port Ethernet1/0/1 of Switch A configuredwith Smart Link group operates normally. Actually, however, the traffic on Switch Acannot 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 detectsthat the link for the uplink port Ethernet1/0/1 fails, all the downlink ports in thegroup are shut down; therefore, Ethernet1/0/3 on Switch C is blocked. Now, SmartLink group configured on Switch A detects that a link fault occurs on the masterport Ethernet1/0/1. Then, Smart Link immediately activates the slave portEthernet1/0/2 so that traffic is switched to the backup link.
