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.Dd $Mdocdate: March 31 2022 $ .Dt VLAN 4 .Os .Sh NAME .Nm vlan , .Nm svlan .Nd IEEE 802.1Q and 802.1ad pseudo-device .Sh SYNOPSIS .Cd "pseudo-device vlan" .Sh DESCRIPTION The .Nm vlan driver provides network interfaces supporting Virtual Local Area Networks (VLANs) on Ethernet networks. .Nm vlan interfaces implement virtual networks using the IEEE 802.1Q protocol. .Nm svlan interfaces implement virtual networks using the IEEE 802.1ad protocol.
p .Nm svlan interfaces allow construction of IEEE 802.1ad-compliant provider bridges. .Nm vlan and .Nm svlan interfaces can be configured to provide QinQ or stacked VLANs.
p The interfaces can be created at runtime using the c ifconfig vlan Ns Ar N Ic create command or by setting up a .Xr hostname.if 5 configuration file for .Xr netstart 8 . The interface itself can be configured with .Xr ifconfig 8 ; see its manual page for more information.
p .Nm vlan and .Nm svlan interfaces must be configured with a parent Ethernet interface to operate, and a virtual network identifier. Packets transmitted through a .Nm vlan or .Nm svlan interface will be encapsulated in their respective protocols and transmitted on the specified physical interface. 802.1Q and 802.1ad packets received on the parent interface will be matched to the .Nm vlan and .Nm svlan interfaces by their respective protocol and virtual network identifiers, and decapsulated for reception on the associated virtual interfaces.
p The 802.1Q and 802.1ad protocols include a priority field. By default, the 802.1p priority in a transmitted packet is based on the priority of packets sent over the interface, which may be altered via .Xr pf.conf 5 ; see the .Cm prio option for more information. Alternatively, .Cm txprio can set a specific priority for transmitted packets.
p .Nm vlan and .Nm svlan interfaces support the following .Xr ioctl 2 Ns s : l -tag -width indent -offset 3n t Dv SIOCSIFPARENT Fa "struct if_parent *" Set the parent interface. The parent may only be configured while the virtual interface is administratively down. t Dv SIOCGIFPARENT Fa "struct if_parent *" Get the currently configured parent interface. t Dv SIOCDIFPARENT Fa "struct ifreq *" Delete the parent interface configuration. The parent may only be removed while the virtual interface is administratively down. t Dv SIOCSVNETID Fa "struct ifreq *" Set the virtual network identifier. Valid identifiers are in the range 1 to 4094. t Dv SIOCGVNETID Fa "struct ifreq *" Get the currently configured virtual network identifier. t Dv SIOCDVNETID Fa "struct ifreq *" Clear the current virtual network identifier. Virtual interfaces without a configured virtual network identifier will use 0 in their protocols tag field. t Dv SIOCSIFLLADDR Fa "struct ifreq *" Configure a custom MAC address on the virtual interface. When the virtual interface is using a custom MAC address, the parent interface will be configured to promiscuously receive packets. When operating without a custom MAC address, the virtual interface will inherit the parent interfaces MAC address. Configuring 00:00:00:00:00:00 as the MAC address will clear the custom MAC address configuration and resume operation with the parents MAC address. .El
p .Nm vlan and .Nm svlan interfaces use the following capability on parent interfaces: l -tag -width "IFCAP_VLAN_HWTAGGING" -offset 3n t IFCAP_VLAN_MTU The parent interface can handle full sized frames, plus the size of the vlan tag. .El
p .Nm vlan interfaces use the following capability on parent interfaces: l -tag -width "IFCAP_VLAN_HWTAGGING" -offset 3n t IFCAP_VLAN_HWTAGGING The parent interface will offload the encapsulation and decapsulation of 802.1Q frames. .El .Sh EXAMPLES Create an 802.1Q virtual interface on top of the physical interface em0, with virtual network identifier 5: d -literal -offset indent # ifconfig vlan0 create # ifconfig vlan0 parent em0 vnetid 5 # ifconfig vlan0 10.1.1.100/24 .Ed
p Create an 802.1Q VLAN interface on network 10, on top of an 802.1ad provider bridge on network 8, on top of the physical interface bge0: d -literal -offset indent # ifconfig svlan0 create # ifconfig svlan0 parent bge0 vnetid 8 # ifconfig svlan0 up # ifconfig vlan0 create # ifconfig vlan0 parent svlan0 vnetid 10 # ifconfig vlan0 10.1.1.101/24 .Ed
p Configure an 802.1Q VLAN interface with a custom MAC address: d -literal -offset indent # ifconfig vlan0 lladdr fe:e1:ba:d0:84:0e .Ed
p Remove a custom MAC address from an 802.1Q VLAN interface: d -literal -offset indent # ifconfig vlan0 lladdr 00:00:00:00:00:00 .Ed
p Force the use of priority 1 for transmitted packets, regardless of the packet priority: d -literal -offset indent # ifconfig vlan0 txprio 1 .Ed .Sh SEE ALSO .Xr inet 4 , .Xr ip 4 , .Xr netintro 4 , .Xr hostname.if 5 , .Xr pf.conf 5 , .Xr ifconfig 8 , .Xr netstart 8 .Rs .%T IEEE 802.1Q standard .%U https://standards.ieee.org/standard/802_1Q-2018.html .Re .Rs .%Q Provider Bridges, QinQ .%T IEEE 802.1ad standard .Re .Sh AUTHORS Originally .An Garrett Wollman Aq Mt wollman@freebsd.org . .Sh CAVEATS Some Ethernet chips will either discard or truncate Ethernet frames that are larger than 1514 bytes. This causes a problem as 802.1Q and 802.1ad tagged frames can be up to 1518 bytes. Most controller chips can be told not to discard large frames and/or to increase the allowed frame size.