How to configure NIC Teaming in Linux

Linux allows binding multiple network interfaces into a single channel/NIC using special kernel module called bonding. The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical “bonded” interface.

 Step #1: Create a bond0 configuration file

Red Hat Linux stores network configuration in /etc/sysconfig/network-scripts/ directory. First, create a bond0 config file:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0

Append following lines to it:

DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

Replace above IP address with your actual IP address. Save file and exit to shell prompt.

 Step #2: Modify eth0 and eth1 config files:

Open both configuration using vi text editor and make sure file read as follows for eth0 interface

 # vi /etc/sysconfig/network-scripts/ifcfg-eth0

Modify/append directive as follows:

DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

 Open eth1 configuration file using vi text editor:

# vi /etc/sysconfig/network-scripts/ifcfg-eth1

Make sure file read as follows for eth1 interface:

DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

Save file and exit to shell prompt.

Step # 3: Load bond driver/module

 Make sure bonding module is loaded when the channel-bonding interface (bond0) is brought up. You need to modify kernel modules configuration file:

# vi /etc/modprobe.conf

Append following two lines:

alias bond0 bonding
options bond0 mode=balance-alb miimon=100

Save file and exit to shell prompt.

 Step # 4: Test configuration

First, load the bonding module:

# modprobe bonding

 Restart networking service in order to bring up bond0 interface:

# service network restart

 Verify everything is working:

# less /proc/net/bonding/bond0

Output:

Bonding Mode: load balancing (round-robin)

MII Status: up

MII Polling Interval (ms): 0

Up Delay (ms): 0

Down Delay (ms): 0

Slave Interface: eth0

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:c6:be:59

 Slave Interface: eth1

MII Status: up

Link Failure Count: 0

Permanent HW addr: 00:0c:29:c6:be:63