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NG_VLAN(4) Device Drivers Manual NG_VLAN(4)


ng_vlanIEEE 802.1Q VLAN tagging netgraph node type


#include <sys/types.h>
#include <netgraph.h>
#include <netgraph/ng_vlan.h>


The vlan node type multiplexes frames tagged according to the IEEE 802.1Q standard between different hooks.

Each node has two special hooks, downstream and nomatch, and an arbitrary number of “vlan” hooks, each associated with a particular VLAN tag.

An ETHERTYPE_VLAN frame received on the downstream hook with a tag that the node has been configured to filter is sent out the corresponding “vlan” hook. If it does not match any of the configured tags, or is not of a type ETHERTYPE_VLAN, it is sent out the nomatch hook. If the nomatch hook is not connected, the packet is dropped.

An Ethernet frame received on the nomatch hook is passed unmodified to the downstream hook.

An Ethernet frame received on any of the “vlan” hooks is tagged accordingly and sent out the downstream hook.


This node type supports the following hooks:

Typically this hook would be connected to a ng_ether(4) node, using the lower hook.
Typically this hook would also be connected to an ng_ether(4) type node using the upper hook.
Any other hook name will be accepted and should later be associated with a particular tag. Typically this hook would be attached to an ng_eiface(4) type node using the ether hook.


This node type supports the generic control messages, plus the following:

Associates a hook with the tag.
Disassociates a hook from the tag.
Returns a table of all hook/tag associations.




ngctl -f- <<EOF
shutdown ${ETHER_IF}:
mkpeer ${ETHER_IF}: vlan lower downstream
name ${ETHER_IF}:lower vlan
connect ${ETHER_IF}: vlan: upper nomatch

ngctl mkpeer vlan: eiface vlan123 ether
ngctl msg vlan: addfilter '{ vlan=123 hook="vlan123" }'


This node shuts down upon receipt of a NGM_SHUTDOWN control message, or when all hooks have been disconnected.


netgraph(4), ng_eiface(4), ng_ether(4), ngctl(8), nghook(8)


The ng_vlan node type appeared in FreeBSD 4.10.


Ruslan Ermilov <>

March 1, 2004 Debian