NIC Bonding On Debian Lenny

Ethernet bonding refers to aggregating multiple ethernet channels together to form a single channel. This is primarily used for redundancy in ethernet paths or for load balancing. This page refers in particular to performing ethernet bonding under Linux, and so does not limit itself to discussion of 802.3ad Trunk Aggregation.


Ethernet Bonding Types

The Linux kernel bonding module supports a number of bonding types.

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) 

One slave interface is active at any time. If one interface fails, another interface takes over the MAC address and becomes the active interface. Provides fault tolerance only. Doesn’t require special switch support

mode=2 (balance-xor) 

Tranmissions are balanced across the slave interfaces based on ((source MAC) XOR (dest MAC)) modula slave count. The same slave is selected for each destination MAC. Provides load balancing and fault tolerance.

mode=3 (broadcast) 

Transmits everything on all slave interfaces. Provides fault tolerance.

mode=4 (802.3ad) 

This is classic IEEE 802.3ad Dynamic link aggregation. This requires 802.3ad support in the switch and driver support for retrieving the speed and duplex of each slave.

mode=5 (balance-tlb) 

Adaptive Transmit Load Balancing. Incoming traffic is received on the active slave only, outgoing traffic is distributed according to the current load on each slave. Doesn’t require special switch support

mode=6 (balance-alb) 

Adaptive Load Balancing - provides both transmit load balancing (TLB) and receive load balancing for IPv4 via ARP negotiation. Doesn’t require special switch support, but does require the ability to change the MAC address of a device while it is open.


Set Up Bonding Ethernet on Debian

To use Bonding Ethernet for High-Availability (fail-over) on Debian Lenny you need to:

Install package ifenslave-2.6. To install this package follow this command:

#apt-get install ifenslave-2.6

Make sure the real NICs kernel modules are loaded automatically.

Edit /etc/network/interfaces to look like this:

iface bond0 inet static
up /sbin/ifenslave bond0 eth0 eth1
down /sbin/ifenslave -d bond0 eth0 eth1

Comment or borrow the lines referring to your real NICs in the same file.

Add the following lines to your /etc/modprobe.d/arch/i386:

alias bond0 bonding
options bonding mode=5 miimon=100 downdelay=200 updelay=200

Make sure you change your mode!

Then restart your networking:

#/etc/init.d/networking restart
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