Bonding, also called port trunking or link aggregation means combining several network interfaces (NICs) to a single link, providing either high-availability, load-balancing, maximum throughput, or a combination of these. See Wikipedia for details.
    Installation
    sudo apt-get install ifenslave
    Interface Configuration
    Step 1: Ensure kernel support
    Before Ubuntu can configure your network cards into a NIC bond, you need to ensure that the correct kernel module bonding is present, and loaded at boot time.
    Edit your /etc/modules configuration:
    sudo vi /etc/modules
    Ensure that the bonding module is loaded:
    # /etc/modules: kernel modules to load at boot time.
    #
    # This file contains the names of kernel modules that should be loaded
    # at boot time, one per line. Lines beginning with “#” are ignored.
    loop
    lp
    rtc
    bonding
    Step 2: Configure network interfaces
    Ensure that your network is brought down:
    sudo stop networking
    Then load the bonding kernel module:
    sudo modprobe bonding
    Now you are ready to configure your NICs.
    A general guideline is to:
    1. Pick which available NICs will be part of the bond.
    2. Configure all other NICs as usual
    3. Configure all bonded NICs:
    1. To be manually configured
    2. To join the named bond-master
    4. Configure the bond NIC as if it were a normal NIC
    5. Add bonding-specific parameters to the bond NIC as follows.
    Edit your interfaces configuration:
    sudo vi /etc/network/interfaces
    For example, to combine eth0 and eth1 as slaves to the bonding interface bond0 using a simple active-backup setup, with eth0 being the primary interface:
    #eth0 is manually configured, and slave to the “bond0” bonded NIC
    auto eth0
    iface eth0 inet manual
    bond-master bond0
    bond-primary eth0
    #eth1 ditto, thus creating a 2-link bond.
    auto eth1
    iface eth1 inet manual
    bond-master bond0
    # bond0 is the bonding NIC and can be used like any other normal NIC.
    # bond0 is configured using static network information.
    auto bond0
    iface bond0 inet static
    address 192.168.1.10
    gateway 192.168.1.1
    netmask 255.255.255.0
    bond-mode active-backup
    bond-miimon 100
    bond-slaves none
    The bond-primary directive, if needed, needs to be part of the slave description (eth0 in the example), instead of the master. Otherwise it will be ignored.
    As another example, to combine eth0 and eth1 using the IEEE 802.3ad LACP bonding protocol:
    #eth0 is manually configured, and slave to the “bond0” bonded NIC
    auto eth0
    iface eth0 inet manual
    bond-master bond0
    #eth1 ditto, thus creating a 2-link bond.
    auto eth1
    iface eth1 inet manual
    bond-master bond0
    # bond0 is the bonded NIC and can be used like any other normal NIC.
    # bond0 is configured using static network information.
    auto bond0
    iface bond0 inet static
    address 192.168.1.10
    gateway 192.168.1.1
    netmask 255.255.255.0
    # bond0 uses standard IEEE 802.3ad LACP bonding protocol
    bond-mode 4
    bond-miimon 100
    bond-lacp-rate 1
    bond-slaves eth0 eth1
    For bonding-specific networking options please consult the documentation available at BondingModuleDocumentation.
    Finally, bring up your network again:
    sudo start networking
    Checking the bonding interface
    Link information is available under /proc/net/bonding/. To check bond0 for example:
    # cat /proc/net/bonding/bond0
    Ethernet Channel Bonding Driver: v3.5.0 (November 4, 2008)
    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
    Aggregator selection policy (ad_select): stable
    bond bond0 has no active aggregator
    Slave Interface: eth1
    MII Status: up
    Link Failure Count: 0
    Permanent HW addr: 00:0c:29:f5:b7:11
    Aggregator ID: N/A
    Slave Interface: eth2
    MII Status: up
    Link Failure Count: 0
    Permanent HW addr: 00:0c:29:f5:b7:1b
    Aggregator ID: N/A
    Bringing up/down bonding interface
    To bring the bonding interface, run
    ifup bond0
    To bring down a bonding interface, run
    ifdown bond0
    Ethernet Bonding modes
    Ethernet bonding has different modes you can use. You specify the mode for your bonding interface in /etc/network/interfaces. For example:
    bond-mode active-backup
    Descriptions of bonding modes
    Mode 0
    balance-rr
    Round-robin policy: Transmit packets in sequential order from the first available slave through the last. This mode provides load balancing and fault tolerance.
    Mode 1
    active-backup
    Active-backup policy: Only one slave in the bond is active. A different slave becomes active if, and only if, the active slave fails. The bond’s MAC address is externally visible on only one port (network adapter) to avoid confusing the switch. This mode provides fault tolerance. The primary option affects the behavior of this mode.
    Mode 2
    balance-xor
    XOR policy: Transmit based on selectable hashing algorithm. The default policy is a simple source+destination MAC address algorithm. Alternate transmit policies may be selected via the xmit_hash_policy option, described below. This mode provides load balancing and fault tolerance.
    Mode 3
    broadcast
    Broadcast policy: transmits everything on all slave interfaces. This mode provides fault tolerance.
    Mode 4
    802.3ad
    IEEE 802.3ad Dynamic link aggregation. Creates aggregation groups that share the same speed and duplex settings. Utilizes all slaves in the active aggregator according to the 802.3ad specification.
    · Prerequisites:
    1. Ethtool support in the base drivers for retrieving the speed and duplex of each slave.
    2. A switch that supports IEEE 802.3ad Dynamic link aggregation. Most switches will require some type of configuration to enable 802.3ad mode.
    o Mode 5
    balance-tlb
    Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.
    · Prerequisites:
    o Ethtool support in the base drivers for retrieving the speed of each slave.
    o Mode 6
    balance-alb
    Adaptive load balancing: includes balance-tlb plus receive load balancing (rlb) for IPV4 traffic, and does not require any special switch support. The receive load balancing is achieved by ARP negotiation. The bonding driver intercepts the ARP Replies sent by the local system on their way out and overwrites the source hardware address with the unique hardware address of one of the slaves in the bond such that different peers use different hardware addresses for the server.
    Descriptions of balancing algorithm modes
    The balancing algorithm is set with the xmit_hash_policy option.
    Possible values are:
    layer2 Uses XOR of hardware MAC addresses to generate the hash. This algorithm will place all traffic to a particular network peer on the same slave.
    layer2+3 Uses XOR of hardware MAC addresses and IP addresses to generate the hash. This algorithm will place all traffic to a particular network peer on the same slave.
    layer3+4 This policy uses upper layer protocol information, when available, to generate the hash. This allows for traffic to a particular network peer to span multiple slaves, although a single connection will not span multiple slaves.
    encap2+3 This policy uses the same formula as layer2+3 but it relies on skb_flow_dissect to obtain the header fields which might result in the use of inner headers if an encapsulation protocol is used.
    encap3+4 This policy uses the same formula as layer3+4 but it relies on skb_flow_dissect to obtain the header fields which might result in the use of inner headers if an encapsulation protocol is used.
    The default value is layer2. This option was added in bonding version 2.6.3. In earlier versions of bonding, this parameter does not exist, and the layer2 policy is the only policy. The layer2+3 value was added for bonding version 3.2.2.

    root@Iaas-zabbix:~# cat /etc/network/interfaces
    # This file describes the network interfaces available on your system
    # and how to activate them. For more information, see interfaces(5).

    # The loopback network interface
    auto lo
    iface lo inet loopback

    # The primary network interface
    auto em1
    iface em1 inet dhcp

    auto p1p1
    iface p1p1 inet manual
    bond-master bond0

    auto p1p2
    iface p1p2 inet manual
    bond-master bond1

    auto p3p1
    iface p3p1 inet manual
    bond-master bond0

    auto p3p2
    iface p3p2 inet manual
    bond-master bond1

    auto bond0
    iface bond0 inet static
    address 10.202.6.80/23
    bond-mode 802.3ad
    bond-miimon 100
    bond-lacp-rate fast
    bond-slaves p1p1 p3p1
    bond-updelay 200
    bond-downdelay 200
    bond-ad-select bandwidth
    bond-xmit-hash-policy layer2+3
    post-up sleep 45

    auto bond1
    iface bond1 inet static
    address 10.202.6.81/23
    bond-mode 802.3ad
    bond-miimon 100
    bond-lacp-rate fast
    bond-slaves p1p2 p3p2
    bond-updelay 200
    bond-downdelay 200
    bond-ad-select bandwidth
    bond-xmit-hash-policy layer2+3
    post-up sleep 45


    # The primary network interface
    allow-hotplug ens3
    iface ens3 inet static
    address 10.201.70.191
    netmask 255.255.255.0
    gateway 10.201.70.254
    dns-nameservers 10.201.70.181,10.201.70.182

    #auto vmbr0
    #iface vmbr0 inet static
    # address 10.201.70.191
    # netmask 255.255.255.0
    # gateway 10.201.70.254
    # dns-nameservers 10.201.70.181,10.201.70.182
    # bridge_ports ens3
    # bridge_stp off
    # bridge_fd 0
    # bridge_maxwait 0
    # bridge_maxage 12
    auto ens10
    iface ens10 inet static
    address 172.16.70.191
    netmask 255.255.255.0