Monitoring an Individual LAG Port

You can monitor the traffic on an individual port of a static LAG group, and on an individual port of an LACP LAG group.

By default, when you monitor the LAG virtual interface, aggregated traffic for all the ports in the LAG is copied to the mirror port. You can configure the device to monitor individual ports in a LAG as well.

To configure port monitoring on an individual port in a LAG, enter commands such as the following.

device(config)# lag automation static id 1
device(config-lag-automation)# ports ethernet 1/1/2 to 1/1/9 
device(config-lag-automation)# exit
device(config)# mirror-port ethernet 1/1/1
device(config)# lag automation 
device(config-lag-automation)# monitor ethe-port-monitored 1/1/2 ethernet 1/1/1 both

device# show mirror
Mirror port 1/1/1
  Input monitoring      : (U1/M1)   1 
  Output monitoring     : (U1/M1)   1

device# show mirror ethernet 1/1/1
Mirror port 1/1/1
  Input monitoring      : (U1/M1)   1 
  Output monitoring     : (U1/M1)   1

device# show running-config | i mirror
mirror-port ethernet 1/1/1

device# show running-config | i monitor ethernet
monitor ethe-port-monitored 1/1/2 ethe 1/1/1 both

Traffic on LAG port e 1/1/2 is monitored, and the monitored traffic is copied to port e 1/1/1, the mirror port.