LAG¶

Link Aggregation (LAG) allows to aggregate multiple network interfaces into a single logical “bonded” interface. It can provide an active backup service assisted with LACP (802.3ad) or a load balancing to increase the bandwidth.

Multiple modes are available for load balancing: round-robin, XOR on MAC address.

Multiple policies are available to select which part of the packet header will be used to compute the hash: L2, L3, L4, mix of L2 and L3, mix of L3 and L4, using either the outer or the most inner packet in case of encapsulation.

By default the MII link monitoring is activated and set to 100 ms. Disabling the MII link monitoring (set its value to 0) is not recommended, the link detection and failure can have poor performance.

To configure a LAG, enter the context interface type lag from the VRF in which you plan to define the LAG interface.

Here is an example of lag named lag0 in VRF main, using lacp mode with a hash on L2+L3 header and a slow rate using two interfaces eth0 and eth1.

running vrf main# interface lag lag0
running vrf main# mode lacp xmit-hash-policy layer2+3 lacp-rate slow
running lag lag0# link-interface eth0
running lag lag0# link-interface eth1
running lag lag0# commit

The lag interface is configured provided eth0 and eth1 are present in VRF main.

Let’s fetch the state after committing this configuration:

running vrf main# interface lag lag0
running lag lag0# show state
lag lag0
    mii-link-monitoring 100
    mode lacp
    xmit-hash-policy layer2+3
    mtu 1500
    lacp-rate slow
    oper-status DOWN
    link-interface eth0
    link-interface eth1
    enabled true
    ethernet
        mac-address f2:a2:6c:f2:9e:e4
        ..
    counters
        in-octets 0
        in-discards 0
        in-errors 0
        out-octets 0
        in-unicast-pkts 0
        out-errors 0
        out-discards 0
        out-unicast-pkts 0
        ..
    ..

The same configuration can be made using this NETCONF XML configuration:

vrouter> show xml absolute config vrf main interface lag lag0
<config xmlns="urn:6wind:vrouter">
  <vrf>
    <name>main</name>
    <interface xmlns="urn:6wind:vrouter/interface">
      <lag xmlns="urn:6wind:vrouter/lag">
        <name>lag0</name>
        <enabled>true</enabled>
        <link-interface>
          <slave>eth0</slave>
        </link-interface>
        <link-interface>
          <slave>eth1</slave>
        </link-interface>
        <ipv4>
          <enabled>true</enabled>
        </ipv4>
        <ipv6>
          <enabled>true</enabled>
        </ipv6>
        <mii-link-monitoring>100</mii-link-monitoring>
        <mode>lacp</mode>
        <xmit-hash-policy>layer2+3</xmit-hash-policy>
        <lacp-rate>slow</lacp-rate>
      </lag>
    </interface>
  </vrf>
</config>