Configure VLAN Tagging on top of LACP Network Bonding using nmcli

In enterprise IT infrastructure, it is common to use LACP Network Bonding and VLAN Tagging.

LACP network bonding allows two or more network interfaces to be aggregated as one, thereby providing increased bandwidth and interface / cable redundancy.

VLAN Tagging allows traffics from different networks to share common physical links while being kept segregated.

To configure both in a Linux server, it is common to use nmcli . Basically, it is a two steps configuration:

1. Configure a network bonding interface to aggregate underlying network interfaces.
2. Configure a VLAN tagged interface on top of the network bonding interface.

Below provides an example to configure these using nmcli on CentOS / RHEL.

Pre-requisites

Ensure to have the 8021q module enabled for LACP.

modprobe --first-time 8021q
modinfo 8021q

Configure Network Bonding

This example adds a network bonding interface named bond0 with two network interfaces named enP48p1s0f0 and enp1s0f0 .

Create the bond0 bonding interface using 802.3ad mode.

nmcli con add type bond ifname bond0 con-name bond0 mode 802.3ad miimon 100 downdelay 0 updelay 0 connection.autoconnect yes ipv4.method disabled ipv6.method ignore

Add the two network interfaces as slave to the bond0 bonding interface.

nmcli con add type bond-slave ifname enP48p1s0f0 con-name enP48p1s0f0 master bond0
nmcli con add type bond-slave ifname enp1s0f0 con-name enp1s0f0 master bond0

Bring up the bond0 bonding interface.

nmcli con up bond0

Check the connections created.

# nmcli con show
NAME         UUID      TYPE      DEVICE
bond0        <masked>  bond      bond0
enP48p1s0f0  <masked>  ethernet  enP48p1s0f0
enp1s0f0     <masked>  ethernet  enp1s0f0

Configure VLAN Tagging

Next, a vlan type connection shall be added on top of the bond0 device created in previous step. The TCP/IP parameters such as IP address, subnet mask, gateway, DNS and search domain are added here as well. In this example, the parameters used are:

• VLAN ID: 123
• IP address: 192.168.123.123
• Subnet mask: 255.255.255.0
• Gateway: 192.168.123.1
• DNS: 192.168.123.4, 192.168.123.5
• Search domain: example.com

nmcli con add type vlan ifname bond0.123 con-name bond0.123 id 123 dev bond0 connection.autoconnect yes ip4 192.168.123.123/24 gw4 192.168.123.1 ipv4.dns 192.168.123.4,192.168.123.5 ipv4.dns-search example.com

Bring up the bond0.123 VLAN interface.

nmcli con up bond0.123

Check the connections created.

# nmcli con show
NAME         UUID      TYPE      DEVICE
bond0        <masked>  bond      bond0
bond0.123    <masked>  vlan      bond0.123
enP48p1s0f0  <masked>  ethernet  enP48p1s0f0
enp1s0f0     <masked>  ethernet  enp1s0f0

Verify the created VLAN interface bond0.123 is UP with IP address configured.

# ip addr show bond0.123
15: bond0.123@bond0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff
    inet 192.168.123.123/24 brd 192.168.123.255 scope global noprefixroute bond0.123
       valid_lft forever preferred_lft forever
    inet6 xxxx::xxxx:xxxx:xxxx:xxxx/64 scope link noprefixroute
       valid_lft forever preferred_lft forever