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Tuesday, August 9, 2011

Network Bonding or Link Aggregation in Linux

Link aggregation or trunking or link bundling or Ethernet/network/NIC bonding or NIC teaming are computer networking umbrella terms to describe various methods of combining (aggregating) multiple network connections in parallel to increase throughput beyond what a single connection could sustain, and to provide redundancy in case one of the links fails.
 The Linux bonding driver provides a method for aggregating multiple network interfaces into a single logical bonded interface. The behavior of the bonded interfaces depends upon the mode; generally speaking, modes provide either hot standby or load balancing services. Additionally, link integrity monitoring may be performed.

Here I am showing you configuration for Centos, it will be same for others, may be some change in file location(depends on distro you are using).

[root@server199 ~]# cd /etc/sysconfig/network-scripts
[root@server199 network-scripts]#
[root@server199 network-scripts]# cat ifcfg-eth0
#Bonding eth0 to bond0
DEVICE=eth0
USERCTL=yes
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
TYPE=Ethernet
HWADDR=00:1c:c0:f8:3e:a9
[root@server199 network-scripts]# cat ifcfg-eth1
# Bonding eth1 to bond0
DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none
TYPE=Ethernet
PEERDNS=yes
IPV6INIT=no
HWADDR=00:06:29:af:c2:6c
[root@server199 network-scripts]#
 
Create a new file called ifcfg-bond0 and below line to it. I am showing contents of file.

[root@server199 network-scripts]# cat ifcfg-bond0
DEVICE=bond0
IPADDR=192.168.2.199
NETMASK=255.255.255.0
TYPE=BOND
GATEWAY=192.168.2.1
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

Now do some changes in /etc/modprobe.conf file by addition of following two lines.


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

Next Restart network service

[root@server199 network-scripts]# service network reload
Shutting down interface bond0:                             [  OK  ]
Shutting down loopback interface:                          [  OK  ]
Disabling IPv4 packet forwarding:  net.ipv4.ip_forward = 0
                                                           [  OK  ]
Bringing up loopback interface:                            [  OK  ]
Bringing up interface bond0:                               [  OK  ]

[root@server199 network-scripts]# ifconfig
bond0     Link encap:Ethernet  HWaddr 00:1C:C0:F8:3E:A9 
          inet addr:192.168.2.199  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::21c:c0ff:fef8:3ea9/64 Scope:Link
          UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
          RX packets:19257 errors:0 dropped:0 overruns:0 frame:0
          TX packets:21223 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:11049157 (10.5 MiB)  TX bytes:2416427 (2.3 MiB)

eth0      Link encap:Ethernet  HWaddr 00:1C:C0:F8:3E:A9 
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:14580 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10688 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:9979659 (9.5 MiB)  TX bytes:1232395 (1.1 MiB)
          Memory:d0a00000-d0a20000

eth1      Link encap:Ethernet  HWaddr 00:06:29:AF:C2:6C 
          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
          RX packets:4677 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10535 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1069498 (1.0 MiB)  TX bytes:1184032 (1.1 MiB)

lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:19508 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19508 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:6175688 (5.8 MiB)  TX bytes:6175688 (5.8 MiB)

Hope it will Help
!Feel free to comment

Kuldeep Sharma