Network Bonding / NIC Teaming in Linux

Network Bonding :- NIC teaming or network bonding is nothing but combining or aggregating multiple network connections in parallel. This is done to increase throughput, and to provide redundancy in case one of the links fails or Ethernet card fails. The Linux kernel comes with the bounding driver for aggregating multiple network interfaces into a single logical interface called bond0.

Bonding is nothing but Linux kernel feature that allows to aggregate multiple like interfaces (such as eth0, eth1) into a single virtual link such as bond0. The idea is pretty simple get higher data rates and as well as link failover. Steps To Configure Bonding in Linux

Step #1: Create a Bond0 Configuration File:

CentOS stores network configuration in /etc/sysconfig/network-scripts/ directory. First, we need to create a bond0 config file as follows:

# vi /etc/sysconfig/network-scripts/ifcfg-bond0
Append the following lines:

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

You need to replace IP address with your actual setup. Save and close the file.

Step #2: Modify eth0 and eth1 config files

Open both configuration Files using a text editor such as vi/vim, 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, enter:

# 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 and close the file.

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

Step # 4: Test configuration

First, load the bonding module, enter:

# modprobe bonding

 

Restart the networking service in order to bring up bond0 interface, enter:

# service network restart

Make sure everything is working. Type the following cat command to query the current status of Linux kernel bounding driver, enter:

# cat /proc/net/bonding/bond0

Sample outputs:

Bonding Mode: load balancing (round-robin)
MII Status: up

MII Polling Interval (ms): 100
Up Delay (ms): 200
Down Delay (ms): 200
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