Ethernet Channel Bonding NIC Teaming on Linux Systems

Ethernet Channel Bonding enables two or more Network Interfaces Card (NIC) to a single virtualNIC card which may increase the bandwidth and provides redundancy ofNIC Cards. This is a great way to achieve redundant links, fault tolerance or load balancing networks in production system. If one physicalNIC is down or unplugged, it will automatically move resources to otherNIC card. Channel/NIC bonding will work with the help of bonding driver inKernel. We’ll be using two NIC to demonstrate the same.

There are almost six types of Channel Bond types are available. Here, we’ll review only two type of Channel Bond which are popular and widely used.

1. 0: Load balancing (Round-Robin) : Traffic is transmitted in sequential order or round-robin fashion from both NIC. This mode provides load balancing and fault tolerance.
2. 1: Active-Backup : Only one slave NIC is active at any given point of time. Other Interface Card will be active only if the active slave NIC fails.

Creating Ethernet Channel Bonding

We have two Network Ethernet Cards i.e eth1 andeth2 where bond0 will be created for bonding purpose. Need superuser privileged to execute below commands.

Load Balancing (Round-Robin)

Configure eth1

Mention parameter MASTER bond0 and eth1 interface as aSLAVE in config file as shown below.

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

DEVICE="eth1"TYPE=EthernetONBOOT="yes"BOOTPROTO="none"USERCTL=noMASTER=bond0SLAVE=yes

Configure eth2

Here also, specify parameter MASTER bond0 and eth2 interface as aSLAVE.

# vi /etc/sysconfig/network-scripts/ifcfg-eth2

DEVICE="eth2"TYPE="Ethernet"ONBOOT="yes"USERCTL=no#NM_CONTROLLED=yesBOOTPROTO=noneMASTER=bond0SLAVE=yes

Create bond0 Configuration

Create bond0 and configure Channel bonding interface in the “/etc/sysconfig/network-scripts/” directory calledifcfg-bond0.

The following is a sample channel bonding configuration file.

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

DEVICE=bond0ONBOOT=yesIPADDR=192.168.246.130NETMASK=255.255.255.0BONDING_OPTS="mode=0 miimon=100"

Note: In the above configuration we have chosen Bonding Optionsmode=0 i.e Round-Robin and miimon=100 (Polling intervals 100 ms).

Let’s see interfaces created using ifconfig command which shows “bond0” running as the MASTER both interfaces “eth1” and “eth2” running asSLAVES.

# ifconfig

bond0     Link encap:Ethernet  HWaddr 00:0C:29:57:61:8E          inet addr:192.168.246.130  Bcast:192.168.246.255  Mask:255.255.255.0          inet6 addr: fe80::20c:29ff:fe57:618e/64 Scope:Link          UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1          RX packets:17374 errors:0 dropped:0 overruns:0 frame:0          TX packets:16060 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:0          RX bytes:1231555 (1.1 MiB)  TX bytes:1622391 (1.5 MiB)eth1      Link encap:Ethernet  HWaddr 00:0C:29:57:61:8E          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1          RX packets:16989 errors:0 dropped:0 overruns:0 frame:0          TX packets:8072 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:1000          RX bytes:1196931 (1.1 MiB)  TX bytes:819042 (799.8 KiB)          Interrupt:19 Base address:0x2000eth2      Link encap:Ethernet  HWaddr 00:0C:29:57:61:8E          UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1          RX packets:385 errors:0 dropped:0 overruns:0 frame:0          TX packets:7989 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:1000          RX bytes:34624 (33.8 KiB)  TX bytes:803583 (784.7 KiB)          Interrupt:19 Base address:0x2080lo        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:8 errors:0 dropped:0 overruns:0 frame:0          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0          collisions:0 txqueuelen:0          RX bytes:480 (480.0 b)  TX bytes:480 (480.0 b)

Restart Network service and interfaces should be OK.

# service network restart

Shutting down interface bond0:                             [  OK  ]Shutting down loopback interface:                          [  OK  ]Bringing up loopback interface:                            [  OK  ]Bringing up interface bond0:                               [  OK  ]

Checking the status of the bond.

# watch -n .1 cat /proc/net/bonding/bond0

Sample Ouput

Below output shows that Bonding Mode is Load Balancing (RR) andeth1 & eth2 are showing up.

Every 0.1s: cat /proc/net/bonding/bond0                         Thu Sep 12 14:08:47 2013 Ethernet Channel Bonding Driver: v3.6.0 (September 26, 2009)Bonding Mode: load balancing (round-robin)MII Status: upMII Polling Interval (ms): 100Up Delay (ms): 0Down Delay (ms): 0Slave Interface: eth1MII Status: upSpeed: UnknownDuplex: UnknownLink Failure Count: 2Permanent HW addr: 00:0c:29:57:61:8eSlave queue ID: 0Slave Interface: eth2MII Status: upSpeed: UnknownDuplex: UnknownLink Failure Count: 2Permanent HW addr: 00:0c:29:57:61:98Slave queue ID: 0

Create Active Backup

In this scenario, Slave interfaces remain same. only one change will be there in the bond interfaceifcfg-bond0 instead of ‘0‘ it will be ‘1‘ which is shown as under.

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

DEVICE=bond0ONBOOT=yesIPADDR=192.168.246.130NETMASK=255.255.255.0BONDING_OPTS="mode=1 miimon=100"

Restart network service and check the status of bonding.

# service network restart

Shutting down interface bond0:                             [  OK  ]Shutting down loopback interface:                          [  OK  ]Bringing up loopback interface:                            [  OK  ]Bringing up interface bond0:                               [  OK  ]

Checking the status of the bond with command.

# watch -n .1 cat /proc/net/bonding/bond0

Sample Output

Bonding Mode is showing fault-tolerance (active-backup) and Slave Interface is up.

Every 0.1s: cat /proc/n...  Thu Sep 12 14:40:37 2013Ethernet Channel Bonding Driver: v3.6.0 (September 26, 2009)Bonding Mode: fault-tolerance (active-backup)Primary Slave: NoneCurrently Active Slave: eth1MII Status: upMII Polling Interval (ms): 100Up Delay (ms): 0Down Delay (ms): 0Slave Interface: eth1MII Status: upSpeed: UnknownDuplex: UnknownLink Failure Count: 0Permanent HW addr: 00:0c:29:57:61:8eSlave queue ID: 0Slave Interface: eth2MII Status: upSpeed: UnknownDuplex: UnknownLink Failure Count: 0Permanent HW addr: 00:0c:29:57:61:98Slave queue ID: 0

Note: Manually down and up the Slave Interfaces to check the working ofChannel Bonding. Please see the command as below.

# ifconfig eth1 down# ifconfig eth1 up

Thats it!

后记：简单的介绍一下上面在加载bonding模块的时候，options里的一些参数的含义：

miimon 监视网络链接的频度，单位是毫秒，我们设置的是200毫秒。

max_bonds 配置的bond口个数

mode bond模式，主要有以下几种，在一般的实际应用中，0和1用的比较多，

如果你要深入了解这些模式各自的特点就需要靠读者你自己去查资料并做实践了。

0或balance-rr 轮转策略，提供负载均衡和耐故障功能，按顺序轮流把包发给包含在bond口内的网口。

1或active-backup 主备策略，提供高耐故障功能，逻辑简单，一个处于激活状态，一个失败，另外一个自动激活。

2或balance-xor XOR策略，提供负载均衡和耐故障功能。

3或broadcast 广播策略，耐故障功能。把数据以广播的方式，发给包含在该bond口内的所有网口。

4或802.3ad IEEE 802.3ad动态链接集合。

5或balance-tlb 自动适应传输负载均衡策略。

6或balance-alb 自动适应负载均衡策略