23.2.3 Configuring LACP link aggregation

(1) Configuring Channel Groups

Points to note

For LACP link aggregation, use the channel-group mode command to specify the channel group number, and either active or passive mode in Ethernet interface configuration mode.

Command examples

1. (config)# interface range gigabitethernet 1/0/1-2

   Places the Switch in Ethernet interface configuration mode for configuring ports 1/0/1 and 1/0/2.

2. (config-if-range)# channel-group 10 mode active

   Adds ports 1/0/1 and 1/0/2 to channel group 10 in LACP mode. If active mode is specified, the LACP starts sending LACPDUs in active mode, independently of the remote device. If passive mode is specified, the LACP starts sending LACPDUs only when LACPDUs are received from the remote device.

(2) Setting System Priority

Set the LACP system priority. For the Switch, the system priority is used for the port detachment restriction functionality, which is an extended function. Normally, you do not need to change the LACP port priority value.

Points to note

The smaller the LACP system priority value set, the higher the priority.

Command examples

1. (config)# lacp system-priority 100

   Sets the LACP system priority level of the Switch to 100.

2. (config)# interface port-channel 10

   (config-if)# channel-group lacp system-priority 50

   Sets the LACP system priority level of channel group 10 to 50. If this change is not made, the system priority level of the switch (100) is used.

(3) Configuring Port Priority

Sets the LACP port priority. For the Switch, the LACP port priority is used for the standby link functionality, which is an extended function. Normally, you do not need to change the LACP port priority value.

Points to note

The smaller the LACP port priority value set, the higher the priority.

Command examples

1. (config)# interface gigabitethernet 1/0/1

   (config-if)# lacp port-priority 100

   Sets the LACP port priority level of port 1/0/1 to 100.

(4) Setting LACPDU Sending Interval

Points to note

The example below shows how to set the interval at which the remote device sends LACPDUs to the Switch. The Switch receives LACPDUs at the set interval.

For the LACPDU sending interval, set long (30 seconds) or short (one second). The default is long (30 seconds). Setting short makes it possible to detect a timeout earlier if a link fault occurs, shortening the length of the communication stoppage.

Command examples

1. (config)# interface port-channel 10

   (config-if)# channel-group periodic-timer short

   Sets the LACPDU sending interval of channel group 10 to short (1 second).

Notes

Although fault detection is earlier with the short setting (1 second), the increased LACPDU traffic adds to the burden of the link aggregation program. If a timeout message is output or if communication often stops temporarily by setting short (1 second), use either the default value of long (30 seconds) or static mode.