VLAN(4) | Device Drivers Manual | VLAN(4) |
vlan
, svlan
— IEEE 802.1Q and 802.1ad pseudo-device
pseudo-device vlan
The vlan
driver provides network
interfaces supporting Virtual Local Area Networks (VLANs) on Ethernet
networks. vlan
interfaces implement virtual networks
using the IEEE 802.1Q protocol. svlan
interfaces
implement virtual networks using the IEEE 802.1ad protocol.
svlan
interfaces allow construction of
IEEE 802.1ad-compliant provider bridges. vlan
and
svlan
interfaces can be configured to provide QinQ
or stacked VLANs.
The interfaces can be created at runtime using the
ifconfig vlan
N
create
command or by setting up a
hostname.if(5) configuration file
for netstart(8). The interface itself
can be configured with ifconfig(8); see
its manual page for more information.
vlan
and svlan
interfaces must be configured with a parent Ethernet interface to operate,
and a virtual network identifier. Packets transmitted through a
vlan
or 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 vlan
and
svlan
interfaces by their respective protocol and
virtual network identifiers, and decapsulated for reception on the
associated virtual interfaces.
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
pf.conf(5); see the
prio
option for more information. Alternatively,
txprio
can set a specific priority for transmitted
packets.
vlan
and svlan
interfaces support the following
ioctl(2)s:
SIOCSIFPARENT
struct if_parent *SIOCGIFPARENT
struct if_parent *SIOCDIFPARENT
struct ifreq *SIOCSVNETID
struct ifreq *SIOCGVNETID
struct if_parent *SIOCDVNETID
struct ifreq *SIOCSIFLLADDR
struct ifreq *vlan
and svlan
interfaces use the following capability on parent interfaces:
vlan
interfaces use the following
capability on parent interfaces:
Create an 802.1Q virtual interface on top of the physical interface em0, with virtual network identifier 5:
# ifconfig vlan0 create # ifconfig vlan0 parent em0 vnetid 5 # ifconfig vlan0 10.1.1.100/24
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:
# 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
Configure an 802.1Q VLAN interface with a custom MAC address:
# ifconfig vlan0 lladdr fe:e1:ba:d0:84:0e
Remove a custom MAC address from an 802.1Q VLAN interface:
# ifconfig vlan0 lladdr 00:00:00:00:00:00
Force the use of priority 1 for transmitted packets, regardless of the packet priority:
# ifconfig vlan0 txprio 1
inet(4), ip(4), netintro(4), hostname.if(5), pf.conf(5), ifconfig(8), netstart(8)
IEEE 802.1Q standard, https://standards.ieee.org/standard/802_1Q-2018.html.
IEEE 802.1ad standard, Provider Bridges, QinQ.
Originally Garrett Wollman <wollman@freebsd.org>.
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.
March 31, 2022 | OpenBSD-current |