1.. _vlan_interface:
2
3Virtual LAN (VLAN) Support
4##########################
5
6.. contents::
7    :local:
8    :depth: 2
9
10Overview
11********
12
13`Virtual LAN <https://wikipedia.org/wiki/Virtual_LAN>`_ (VLAN) is a
14partitioned and isolated computer network at the data link layer
15(OSI layer 2). For ethernet network this refers to
16`IEEE 802.1Q <https://en.wikipedia.org/wiki/IEEE_802.1Q>`_
17
18In Zephyr, each individual VLAN is modeled as a virtual network interface.
19This means that there is an ethernet network interface that corresponds to
20a real physical ethernet port in the system. A virtual network interface is
21created for each VLAN, and this virtual network interface connects to the
22real network interface. This is similar to how Linux implements VLANs. The
23*eth0* is the real network interface and *vlan0* is a virtual network interface
24that is run on top of *eth0*.
25
26VLAN support must be enabled at compile time by setting option
27:kconfig:`CONFIG_NET_VLAN` and :kconfig:`CONFIG_NET_VLAN_COUNT` to reflect how
28many network interfaces there will be in the system.  For example, if there is
29one network interface without VLAN support, and two with VLAN support, the
30:kconfig:`CONFIG_NET_VLAN_COUNT` option should be set to 3.
31
32Even if VLAN is enabled in a :file:`prj.conf` file, the VLAN needs to be
33activated at runtime by the application. The VLAN API provides a
34:c:func:`net_eth_vlan_enable` function to do that. The application needs
35to give the network interface and desired VLAN tag as a parameter to that
36function. The VLAN tagging for a given network interface can be disabled by a
37:c:func:`net_eth_vlan_disable` function. The application needs to configure
38the VLAN network interface itself, such as setting the IP address, etc.
39
40See also the :ref:`VLAN sample application <vlan-sample>` for API usage
41example. The source code for that sample application can be found at
42:zephyr_file:`samples/net/vlan`.
43
44The net-shell module contains *net vlan add* and *net vlan del* commands
45that can be used to enable or disable VLAN tags for a given network interface.
46
47See the `IEEE 802.1Q spec`_ for more information about ethernet VLANs.
48
49.. _IEEE 802.1Q spec: https://ieeexplore.ieee.org/document/6991462/
50
51API Reference
52*************
53
54.. doxygengroup:: vlan_api
55