How to Configure Network Bonding in Linux

How to configure network bonding in
Linux

Configuring the switch for LACP bonding

Cisco IOS switch LACP configuration
Enabling LACP across two ports in IOS is pretty straightforward. The first thing to do is
associate the ports with the channel-group. This is good to do early so that when you
apply switchport parameters to the Port-channel interface it automagically applies them to
the GigabigEthernet interfaces.
Here are the relevant portions of my running configuration.
interface Port-channel2
description LACP Channel for mk2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,2
switchport mode trunk
spanning-tree portfast trunk
!
interface GigabitEthernet1/0/23
description mk2 eth0
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 2 mode active
!
interface GigabitEthernet1/0/24
description mk2 eth1
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 2 mode active
!


Configuring the Linux host for LACP
bonding:

There are a few places where you define the parameters of the bond. The kernel module
defies the protocol, frequency and other attributes of the low-level bond channel
configuration. The command ifenslave will create a bond device and allow you to manage
the Ethernet devices within it (add/remove,etc.). Finally the network address configuration
is handled by ifconfig, consistent with most other network interfaces in Linux. Luckily
most of this is taken care of automatically by the networking init scripts.
Linux Kernel Module Configuration

LACP is referred to in linux as bonding mode 4, so we need to inform the kernel module
to use this bonding mode. We’ll also pass it a few other parameters like the frequency of
which to scan for changes in status.
Add the following to your module config file, in gentoo this is
/etc/modules.autoload.d/kernel-2.6. This will pass the following options to the kernel
module the next time it is inserted.
Red Hat and CentOS Kernel Module
Configuration
#/etc/modprobe.conf

alias bond0 bonding
options bond0 miimon=100 mode=4 lacp_rate=1


Linux Network Configuration

Red Hat and CentOS Network Setup
#/etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
MASTER=bond0
SLAVE=yes
#/etc/sysconfig/network-scripts/ifcfg-eth1

DEVICE=eth1
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
MASTER=bond0
SLAVE=yes
#/etc/sysconfig/network-scripts/ifcfg-bond0

DEVICE=bond0
IPADDR=10.0.0.80
NETMASK=255.255.255.0
BROADCAST=10.0.0.255
GATEWAY=10.0.0.1
ONBOOT=yes
BOOTPROTO=none
USERCTL=no






Checking the Status of the bonded
interface

You can check the status of your bond now from within Linux by using the /proc and /sys
interfaces into the Linux bond driver.
$ cat /proc/net/bonding/bond0

Ethernet Channel Bonding Driver: v3.1.1 (September 26, 2006)

Bonding Mode: IEEE 802.3ad Dynamic link aggregation
Transmit Hash Policy: layer2 (0)
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

802.3ad info
LACP rate: fast
Active Aggregator Info:
Aggregator ID: 1
Number of ports: 2
Actor Key: 17
Partner Key: 1
Partner Mac Address: 00:77:54:71:a8:6f

Slave Interface: eth0
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:99:97:60:9d:48
Aggregator ID: 1

Slave Interface: eth1
MII Status: up
Link Failure Count: 0
Permanent HW addr: 00:00:85:60:9d:49
Aggregator ID: 1
You can check the bond from the switch.
Cisco IOS
Switch#show interfaces Port-channel 2
Port-channel2 is up, line protocol is up (connected)
Hardware is EtherChannel, address is 001b.0dbf.ba17 (bia
001b.0dbf.ba17)
Description: LACP Channel for mk2
MTU 1500 bytes, BW 2000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Full-duplex, 1000Mb/s, link type is auto, media type is unknown
input flow-control is off, output flow-control is unsupported
Members in this channel: Gi1/0/23 Gi1/0/24
ARP type: ARPA, ARP Timeout 04:00:00
Last input 1d23h, output 00:00:01, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops:
0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 5000 bits/sec, 7 packets/sec
1060041 packets input, 193406916 bytes, 0 no buffer
Received 18241 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 11873 multicast, 0 pause input
0 input packets with dribble condition detected
3181997 packets output, 2735804051 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 PAUSE output
0 output buffer failures, 0 output buffers swapped out