7.4. Configure 802.1Q VLAN Tagging Using the Command Line Tool, nmcli
To create an 802.1Q VLAN interface on Ethernet interface
eth0, with VLAN interface
VLAN10 and ID
10, issue a command as follows:
~]$ nmcli con add type vlan ifname VLAN10 dev eth0 id 10
Connection 'vlan-VLAN10' (37750b4a-8ef5-40e6-be9b-4fb21a4b6d17) successfully added.
Note that as no
con-name was given for the VLAN interface, the name was derived from the interface name by prepending the type. Alternatively, specify a name with
con-name as follows:
~]$ nmcli con add type vlan con-name VLAN12 dev eth0 id 12
Connection 'VLAN12' (b796c16a-9f5f-441c-835c-f594d40e6533) successfully added.
Further options for the VLAN command are listed in the VLAN section of the nmcli(1) man page. In the man pages the device on which the VLAN is created is referred to as the parent device. In the example above the device was specified by its interface name, eth0, it can also be specified by the connection UUID or MAC address.
To create an 802.1Q VLAN connection profile with ingress priority mapping on Ethernet interface
eth1, with name
VLAN1 and ID
13, issue a command as follows:
~]$ nmcli con add type vlan con-name VLAN1 dev eth2 id 13 ingress "2:3,3:5"
To view all the parameters associated with the VLAN created above, issue a command as follows:
~]$ nmcli connection show vlan-VLAN10
To change the MTU, issue a command as follows:
~]$ nmcli connection modify vlan-VLAN10 802.mtu 1496
The MTU setting determines the maximum size of the network layer packet. The maximum size of the payload the link-layer frame can carry in turn limits the network layer MTU. For standard Ethernet frames this means an MTU of 1500 bytes. It should not be necessary to change the MTU when setting up a VLAN as the link-layer header is increased in size by 4 bytes to accommodate the 802.1Q tag.
At time of writing,
connection.interface-name and
vlan.interface-name have to be the same (if they are set). They must therefore be changed simultaneously using
nmcli's interactive mode. To change a VLAN connections name, issue commands as follows:
~]$ nmcli con edit vlan-VLAN10
nmcli> set vlan.interface-name superVLAN
nmcli> set connection.interface-name superVLAN
nmcli> save
nmcli> quit
The
nmcli utility can be used to set and clear
ioctl flags which change the way the 802.1Q code functions. The following VLAN flags are supported by
NetworkManager:
The state of the VLAN is synchronized to the state of the parent or master interface (the interface or device on which the VLAN is created). If the parent interface is set to the
“down” administrative state then all associated VLANs are set down and all routes are flushed from the routing table. Flag
0x04 enables a
loose binding mode, in which only the operational state is passed from the parent to the associated VLANs, but the VLAN device state is not changed.
To set a VLAN flag, issue a command as follows:
~]$ nmcli connection modify vlan-VLAN10 vlan.flags 1
