Monitoring LAG Virtual Interface and Individual LAG Port

Once a LAG is created, monitoring across all ports of the LAG can be configured on the LAG virtual interface. You can configure the device to monitor individual ports in a LAG, including Ethernet or named ports. You can monitor each of the member ports individually. If a new port is added to a LAG and the entire LAG is monitored, the new port will also be mirrored by the same port monitoring traffic across the entire LAG.
Note: You can use only one mirror port for each monitored LAG port.

Complete the following steps to monitor LAG virtual interface.

  1. In global configuration mode, use the mirror-port ethernet 3/1/1 command.
    device(config)# mirror-port ethernet 3/1/1
  2. Enter the lag blue dynamic id 1 to enter LAG mode.
    device(config)# lag blue dynamic id 1
  3. In the LAG mode, enter the ports ethernet 1/1/1 to 1/1/2 ethernet 2/1/3 to 2/1/4 command.
    device(config-lag-blue)# ports ethernet 1/1/1 to 1/1/2 ethernet 2/1/3 to 2/1/4
  4. In global configuration mode, use the interface lag 1 command to enter LAG mode.
    device(config)# interface lag 1
  5. Enter the monitor both command.
    device(config-lag-if-lg1)# monitor both
  6. Enter the exit command to exit from the LAG mode..
    device(config-lag-if-lg1)# exit
  7. To view the running configurations, enter the show mirror command.
    device(config)# show mirror

The following example monitors the LAG virtual interface

device(config)# mirror-port ethernet 3/1/1
device(config)# lag blue dynamic id 1
device(config-lag-blue)# ports ethernet 1/1/1 to 1/1/2 ethernet 2/1/3 to 2/1/4
device(config)# interface lag 1
device(config-lag-if-lg1)# monitor both
device(config-lag-if-lg1)# exit
device(config)# show mirror
Mirror port 3/1/1
Input monitoring : (U1/M1) 1 2
Input monitoring : (U2/M1) 3 4
Input monitoring : (LAG) 1
Output monitoring : (U1/M1) 1 2
Output monitoring : (U2/M1) 3

Example of Monitoring an Individual LAG Port

To monitor traffic on an individual port in a LAG, use the following commands.
device(config)# lag blue static id 1
device(config-lag-blue)# ports ethernet 1/1/1 ethernet 1/1/47
device(config-lag-blue)# monitor ethe-port-monitored 1/1/47 ethernet 1/1/15 output