932 CHAPTER 85: M ONITOR L INK CONFIGURATIONHow Monitor LinkWorksFigure 260 Network diagram for a Monitor Link group implementationAs shown in Figure 260, the devices Switch C and Switch D are connected to theuplink device Switch E. Switch C is configured with a Monitor Link group, whereEthernet2/0/1 is the uplink port, while Ethernet2/0/2 and Ethernet2/0/3 are thedownlink ports. Switch A is configured with a Smart Link group, whereEthernet2/0/1 is the master port and Ethernet2/0/2 is the slave port.■ If Switch C is not configured with Monitor Link group, when the link for theuplink port Ethernet2/0/1 on Switch C fails, the links in the Smart Link groupare not switched because the link for the master port Ethernet2/0/1 of SwitchA configured with Smart Link group operates normally. Actually, however, thetraffic on Switch A cannot be up-linked to Switch E through the link ofEthernet2/0/1.■ If Switch C is configured with Monitor Link group and Monitor Link groupdetects that the link for the uplink port Ethernet2/0/1 fails, all the downlinkports in the group are shut down; therefore, Ethernet2/0/3 on Switch C isblocked. Now, Smart Link group configured on Switch A detects that a linkfault occurs on the master port Ethernet2/0/1. Then, Smart Link immediatelyactivates the slave port Ethernet2/0/2 so that traffic is switched to the backuplink.n ■ Currently, member ports of a Monitor Link group cannot be dynamic linkaggregation groups.■ If the uplink or downlink port in the Monitor Link group is a link aggregationgroup, you cannot directly delete this aggregation group or change thisaggregation group into a dynamic aggregation group. To delete thisaggregation group, you must first unbind this aggregation group from theMonitor Link.Configuring MonitorLinkn Before configuring a Monitor Link group, you must create a Monitor Link groupand configure member ports for it. A Monitor Link group consists of an uplink portBLOCKSwitch A Switch BEth 2/ 0/ 1 Eth 2/0/ 2Switch C Switch DSwitch EEth 2/ 0/ 1Eth 2/ 0/ 2Eth 2/ 0/ 3Eth 2 /0 / 1Eth 1/ 0/ 2Eth 2 /0/ 11 Eth 2 /0 / 12
