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Bonding Ethernet Interfaces in RHEL 7

News Trunking / Bonding Multiple Network Interfaces Recommended Links

Link aggregation

Bonding Ethernet Interfaces in RHEL 7 Bonding Ethernet Interfaces in RHEL 6 Bonding Multiple Network Interfaces in SLES
Internet Layer of TCP/IP Protocol IEEE 802.3ad Dynamic link aggregation          
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The Linux bonding driver provides a method for aggregating multiple network interface controllers (NICs) into a single logical bonded interface of two or more so-called (NIC) slaves. RHEL has the Linux bonding driver integrated as a loadable kernel module and the ifenslave (if = [network] interface) user-level control program pre-installed. Donald Becker programmed the original Linux bonding driver. It came into use with the Beowulf cluster patches for the Linux kernel 2.0.

Link aggregation offers an inexpensive way to set up a high-speed backbone network that transfers much more data than any single port or device can deliver. Link aggregation also allows the network's backbone speed to grow incrementally as demand on the network increases, without having to replace everything and deploy new hardware.

Linux implements Ethernet bonding (trunking) at a higher level then Microsoft Windows, and can hence deal with NICs from different manufacturers or drivers, as long as the NIC is supported by the kernel.

With the modes balance-rr, balance-xor, broadcast and 802.3ad, all physical ports in the link aggregation group must reside on the same logical switch, which, in most common scenarios, will leave a single point of failure when the physical switch to which all links are connected goes offline. The modes active-backup, balance-tlb, and balance-alb can also be set up with two or more switches. But after failover (like all other modes), in some cases, active sessions may fail (due to ARP problems) and have to be restarted.

On Ethernet interfaces level  bonding requires assistance from both the Ethernet switch and the host computer's operating system, which must "stripe" the delivery of frames across the network interfaces in the same manner as I/O is striped across disks in a RAID 0 array. For this reason, bonding sometimes is called Redundant Array of Inexpensive Nodes (RAIN) or to "redundant array of independent network interfaces".

There are two types on bonding:

There are 6 bonding modes

Note: you can always append extra configuration in case of a rollback.

In one bonding mode does not work you can try another. This is kind of simplistic troubleshooting but it often works.

The following table describes the required configuration that you must apply to the upstream switch depending on the bonding mode (7.6. Overview of Bonding Modes and the Required Settings on the Switch Red Hat Enterprise Linux 7 ):

Table 7.1. Switch Configuration Settings Depending on the Bonding Modes

Bonding Mode Configuration on the Switch
0 - balance-rr Requires static Etherchannel enabled (not LACP-negotiated)
1 - active-backup Requires autonomous ports
2 - balance-xor Requires static Etherchannel enabled (not LACP-negotiated)
3 - broadcast Requires static Etherchannel enabled (not LACP-negotiated)
4 - 802.3ad Requires LACP-negotiated Etherchannel enabled
5 - balance-tlb Requires autonomous ports
6 - balance-alb Requires autonomous ports

Most commonly bonding is needed only on one end (on the server). This most typical case is when four 10Gbit interfaces are bonded to create a single 40Gbit interface using special cable and 40 Gbit port on the switch.


For a bonding interface to be valid, the kernel module must be loaded. In RHEL 7, the bonding module is not loaded by default. You need to load the module by issuing the following command as root:

modprobe --first-time bonding

This activation will not persist across system restarts. See the How do I load kernel modules during boot time in RHEL 7 or 8- - Red Hat Customer Portal  for an explanation of persistent module loading. See also man-page modules-load.d(5) [centos ]


Recommended: Use systemd-modules-load.service to load the modules during boot.

  1. Add a file in /etc/modules-load.d/<name>.conf containing module names. It will read the lines in order and load the modules sequentially.

    # Load the below modules at boot
  2. Run the below command to start the systemd service,

    # systemctl enable systemd-modules-load
    # systemctl restart systemd-modules-load

 Example: /etc/modules-load.d/bonding.conf example:

# Load bonding.ko at boot

To display information about the module, issue the following command:

modinfo bonding

Creating bonded interface by directly edition interface files

RHEL 7 can be configured like RHEL6 by checking in appropriate module (called bonding) is loaded, then directly editing interface file and reloading the netwrok via systemdcrl after that. To create a channel bonding interface, create a file in the /etc/sysconfig/network-scripts/ directory called ifcfg-bond<N> , replacing <N> with the number for the interface, such as 0. The contents of the file can be identical to whatever type of interface is getting bonded, such as an Ethernet interface. The only difference is that the DEVICE= directive must be bond<N> , replacing <N> with the number for the interface.

The following is a sample channel bonding configuration file, ifcfg-bond0 (example from Setting up channel bonding on RHEL 7):

Figure 4. Example: RHEL 7--Configuration file of a bonding master


After the channel bonding interface is created, the network interfaces to be bound together must be configured by adding the MASTER= and SLAVE= directives to their configuration files. The configuration files for each of the channel-bonded interfaces can be nearly identical.

Step1. Log on to server and run the ip a command to check the available interfaces.

Step2. Load the bonding driver called “bonding” in the kernel with the modprobe command if it is not already loaded, and verify with the modinfo command:

modprobel bonding
modinfo bonding 
lsmod | grep bonding

Step3. Generate UUIDs for interfaces using the uuidgen command.

uuidgen bond0

Step4. Use the vi editor to create a file called ifcfg-bond0 in the /etc/sysconfig/network-scripts directory for bond0 with the following settings. Use the interface type bond. This virtual device will serve as the bonding maste.

Step5. Use the vi editor to modify each of interfaces you bond together (for example ifcfg-eth1 and ifcfg-eth2) in the /etc/sysconfig/network-scripts directory. Set the MASTER directive to bond0. Add SLAVE=yes directive to both eth2 and eth3.

For example, if two Ethernet interfaces are being channel bonded, both eth0 and eth1 may look like the following example:


Step6. Deactivate and reactivate bond0 with the ifdown and ifup commands. You can also use systemctl restart network

ifdown bond0; ifup bond0

Step7. Check the status of bond0 and the slaves with the ip command. It should also show the assigned IP.

ip addr
cat /proc/net/bonding/bond0

Step8. Restart the system to ensure the configuration survives system reboots:

Creation of bonding interface using nmtui

Red hat documentation cover this at 7.2. Configure Bonding Using the Text User Interface, nmtui Red Hat Enterprise Linux 7 - Red Hat Customer Portal

You can also look at rewrite at  How to Setup and Configure Network Bonding or Teaming in RHEL-CentOS 7 - Part 11  

Creation of bonding interface using nmcli

You can do it directly as described in Network Bonding Using the NetworkManager Command Line Tool, nmcli Red Hat Enterprise Linux 7 - Red Hat Customer Portal

Red Hat Customer Portal Labs provides a Network Bonding Helper for automatically generating a network bond, based on your environment and deployment goals. (See "Red Hat Network Bonding Helper" []). This is a web application that helps generate configuration files with the setup information given by user.

Note:  Be sure to review  the configuration files before applying to the system.


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Configuring Interface Bonding on CentOS-RHEL-OEL 6.x Toki Winter

In my previous article I wrote about configuring configuring network interface bonding under Debian Wheezy. Here, I'll briefly outline the steps required to get the same configuration running under recent RHEL-flavoured distributions – namely CentOS 6.4 in my case.

I will be bonding eth0 and eth1 into a bond named bond0. Ensure that you're connected to your host via a console. I'll be using active-backup (i.e. failover) bonding, but there are other options available – see the Debian article for links to reference material for those.

First, create the ifcfg-bond0 configuration file:

RHEL 6 - New Network Bonding Configuration - FATMIN

September 12, 2011

Due to the fact that /etc/modprobe.conf has been deprecated in RHEL 6, the process of bonding network interfaces has changed a bit.

Now instead of defining your bond in your /etc/modprobe.conf, you define it in /etc/modprobe.d/bonding.conf. No changes in syntax.

alias bond0 bonding

Then in your ifconfig-bond0 file, you define your bonding mode. Note the quotes, and the fact that I explicitly typed out the bonding mode

Bonding Ethernet Interfaces in Linux

This short HOWTO will tell you how to 'bond' two (or more) physical ethernet interfaces together to look and act as a single interface under Linux.

It was originally written for Mandrakelinux users but it has also been tested on recent versions of Mandriva Linux.


This example assumes you have two interfaces and want to use them in a 'fail-over' setup, where if one cable dies, the kernel will automatically switch to using the other cable.. This setup is quite common on server hardware.

In /etc/modules.conf on a 2.4.x kernel, or in /etc/modprobe.conf on a 2.6.x kernel, you should have something similar to the following:

	alias eth0 e1000	# Intel GigE (pci) port 1
	alias eth1 e1000	# Intel GigE (pci) port 2

	alias bond0 bonding				# Kernel nic bonding driver
	alias bond1 bonding				# Another bonded interface
	options bond0 max_bonds=2 miimon=100 mode=1	# 100ms fail-over timer. Mode 1 = Active/Backup
	options bond1 miimon=100 mode=1			# Same for bond1 

You need the following files in /etc/sysconfig/network-scripts/ :


ifcfg-eth0 and ifcfg-eth1 should look similar to the following:


The DEVICE= section should reflect the interface the file relates to (ifcfg-eth1 should have DEVICE=eth1). The MASTER= section should indicate the bonded interface to be used. Assign both e1000 devices to bond0.

The bond0 file contains the actual IP address information:


Simply restarting the network service 'service network restart' should present you with a new 'bond0' interface. This is the interface you should see traffic going in and out of if youwere to tcpdump the interface.

You will also notice (using /sbin/ifconfig) that all of the ethX interfaces are also up, and also have IP addresses.

bond0     Link encap:Ethernet  HWaddr 00:04:23:61:06:30
	  inet addr:  Bcast:  Mask:
          inet6 addr: fe80::204:23ff:fe61:630/64 Scope:Link
          RX packets:240339580 errors:0 dropped:0 overruns:0 frame:0
          TX packets:264367658 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:3328878476 (3174.6 Mb)  TX bytes:2497930422 (2382.2 Mb)

eth0      Link encap:Ethernet  HWaddr 00:04:23:61:06:30
          inet6 addr: fe80::204:23ff:fe61:630/64 Scope:Link
          RX packets:43224057 errors:0 dropped:0 overruns:0 frame:0
          TX packets:50149177 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:965949319 (921.2 Mb)  TX bytes:3242163496 (3091.9 Mb)
          Base address:0xdcc0 Memory:fcfa0000-fcfc0000

eth1      Link encap:Ethernet  HWaddr 00:04:23:61:06:30
          inet6 addr: fe80::204:23ff:fe61:630/64 Scope:Link
          RX packets:197115526 errors:0 dropped:0 overruns:0 frame:0
          TX packets:214218484 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2362929367 (2253.4 Mb)  TX bytes:3550735168 (3386.2 Mb)
          Base address:0xdc80 Memory:fcf80000-fcfa0000

In this example, we are using the fail-over mode. The eth device without NOARP is the current active SLAVE. You may notice that both ethX interfaces have high traffic counters. This is because the system has been up for around 200 days and at some point the interfaces swapped status.

For further reading, you should also read /usr/src/linux/Documentation/networking/bonding.txt which also gives the different bonding modes you can use. Some of these (like Etherchannel trunking) need compatible switches.

Debian - Ubuntu Linux Configure Network Bonding by nixCraft

Sep 4, 2011

Debian / Ubuntu Linux: Configure Network Bonding [ Teaming / Aggregating NIC ]

by NIX Craft on · 19 comments· LAST UPDATED September 6, 2011

in Debian Linux

NIC teaming 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. In this tutorial, I will explain how to setup bonding under Debian Linux server to aggregate multiple Ethernet devices into a single link, to get higher data rates and link failover.

The instructions were tested using the following setup:
◾2 x PCI-e Gig NIC with jumbo frames.
◾RAID 6 w/ 5 enterprise grade 15k SAS hard disks.
◾Debian Linux 6.0.2 amd64

Please note that the following instructions should also work on Ubuntu Linux server.

RHEL: Linux Bond / Team Multiple Network Interfaces (NIC) Into a Single Interface by NIX Craft

April 3, 2006


Finally, today I had implemented NIC bounding (bind both NIC so that it works as a single device). 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. The following instructions were tested on:

  1. RHEL v4 / 5 / 6 amd64
  2. CentOS v5 / 6 amd64
  3. Fedora Linux 13 amd64 and up.
  4. 2 x PCI-e Gigabit Ethernet NICs with Jumbo Frames (MTU 9000)
  5. Hardware RAID-10 w/ SAS 15k enterprise grade hard disks.
  6. Gigabit switch with Jumbo Frame

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