Bonding Network Cards & Load Balancing in Ubuntu Server 10.4 LTS

Afters a couple of hours wasted looking online for the answers I ended up coming up with my own. I use vim as my text editor sooooo… if you use nano or whatever just use that.

The Following configuration is ideal for Load Balancing scenarios, you can find our more about different bond modes at the bottom of the post.


Lets install the correct software to support the bonding…
sudo apt-get install ifenslave 


open up a shell/terminal window and edit…
sudo vim /etc/network/interfaces


Copy this info, replacing the ip’s provided with your own…

#The Loopback Network Interface

auto lo
iface lo inet loopback

#The Primary Network Interface

iface eth0 inet manual
iface eth1 inet manual
auto bond0

iface bond0 inet static
bond_miimon 100
bond_mode balance-rr
address 192.168.1.x <——————- USE YOUR OWN LOCAL IP (ASSIGN IT ONE)
up ifenslave bond0 eth0 eth1
down ifenslave -d bond0 eth0 eth1

Save and exit


now open aliases.conf…
sudo vim /etc/modprobe.d/aliases.conf


copy this…

alias bond0 bonding
options bonding mode=0 miimon=100 downdelay=200 updelay=200


Save, Exit and Reboot your computer…
sudo reboot


This is tested and working in a live environment with dual GB nics, if you have any problems or would like to bond more then 2 nics leave a comment as the topic is beyond this quick post.



mode=0 (balance-rr) Round-robin policy: Transmit packets in sequential order from the first available slave through the last. This mode provides load balancing and fault tolerance.

mode=1 (active-backup) Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond’s MAC address is externally visible on only one port (network adapter) to avoid confusing the switch. This mode provides fault tolerance. The primary option affects the behavior of this mode.

mode=2 (balance-xor) XOR policy: Transmit based on [(source MAC address XOR’d with destination MAC address) modulo slave count]. This selects the same slave for each destination MAC address. This mode provides load balancing and fault tolerance.

mode=3 (broadcast) Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.

mode=4 (802.3ad) IEEE 802.3ad Dynamic link aggregation. Creates aggregation groups that share the same speed and duplex settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification.

  • Pre-requisites:
  • Ethtool support in the base drivers for retrieving the speed and duplex of each slave.
  • A switch that supports IEEE 802.3ad Dynamic link aggregation. Most switches will require some type of configuration to enable 802.3ad mode.

mode=5 (balance-tlb) Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

* Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.

mode=6 (balance-alb) Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server.