6.3. SubinterfacesΒΆ

A single data interface or bond can be divided into several logical subinterfaces using a VLAN ID tag in accordance with the IEEE 802.1Q standard.

Logical subinterfaces can be used to isolate traffic from different VLANs using VRFs, as well as, for example, to separate inbound and outbound NAT traffic.

To create a logical subinterface, use the command:

interface IFNAME

The IFNAME parameter is specified in the NAME.ID format, where NAME - is the name of the interface for which the subinterface is being created, and ID - is the VLAN ID which traffic will be isolated.

The same commands are available for configuring subinterfaces as for normal data interfaces, with the following limitations:

  • the subinterface cannot be added to the bond,

  • the subinterface inherits the MTU of the parent interface.