Kemp Support, how can we help?

The latest application delivery knowledge and expertise at your fingertips.

Configuring Interface Link Aggregation (Bonding) On The LoadMaster

The LoadMaster has the ability to bond its interfaces together to provide for additional throughput as well as redundancy. The LoadMaster supports two styles of bonding: 802.3ad and Active-Backup.

Before creating a bonded interface please note the following:

  • You can only bond interfaces higher than the parent, so if you choose to start with port 10 then you can only add ports 11 and greater
  • Bond links first. If you need VLAN tagging, add VLANs after the bond has been configured
  • In order to add a link to a bonded interface, any IP addressing must first be removed from the link to be added
  • Enabling the Active-Backup mode generally does not require switch intervention
  • Bonding eth0 with eth1 can lead to serious issues and is not supported

To configure an interface for use with bonding, follow the steps below in the LoadMaster Web User Interface (WUI):

  1. In the main menu, select System Configuration.
  2. Select the lowest indexed interface you want to use, for example, eth0.
  3. Click the Interface Bonding button.
  4. Click Create a bonded interface.

          This will turn eth* to bnd*.

  1. In the main menu, select System Configuration and bnd*.
  2. Configure the addressing as needed.
  3. To add interfaces or to modify the bond type click Bonded Devices.
  4. You can select the style of bonding in the Bonding mode drop-down list:


  • 802.3ad – True bonding which aggregates the bandwidth of multiple interfaces. Both interfaces must connect to the same switch and the switch ports must be configured to support this.
  • Active-backup – This style of bonding allows for link redundancy but does not aggregate the bonded interfaces. Each link can be connected to a different switch for full redundancy. No switch configuration is required for this.

When using 802.3ad Link Aggregation on the LoadMaster interfaces, it is necessary that the link partner (usually a switch that the LoadMaster is connected to) is configured correctly to also use the same Link Aggregation protocol. If your switch (or other devices) is not properly configured, you will not be able to connect to the LoadMaster on the bonded interface and a message will appear similar to this in the LoadMaster log files:

kernel: bonding: bnd0: Warning: No 802.3ad response from the link partner for any adapters in the bond.

If you experience these symptoms it is important to check that the switch supports 802.3ad and that the ports which the LoadMaster is connected to are properly configured as a Link Aggregation Group. The steps required to configure the ports will vary from switch to switch so if you are unsure you should consult with the switch manufacturer for further assistance.

If you find your switch does not support 802.3ad, or you need a workaround to provide high availability for the interfaces while investigating, you can change the bond type on the LoadMaster to Active-backup instead of 802.3ad. This mode should work on any switch type without special configuration.

If this still does not work, remove the bonded interface and try setting up the network using a single interface to ensure the problem is not related to something else on the network.

Was this article helpful?
0 out of 0 found this helpful