47 lines
2.1 KiB
ReStructuredText
47 lines
2.1 KiB
ReStructuredText
.. _vlan-support:
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Virtual LAN (VLAN) Support
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##########################
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Overview
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********
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`Virtual LAN <https://wikipedia.org/wiki/Virtual_LAN>`_ (VLAN) is a
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partitioned and isolated computer network at the data link layer
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(OSI layer 2). For ethernet network this refers to
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`IEEE 802.1Q <https://en.wikipedia.org/wiki/IEEE_802.1Q>`_
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In Zephyr, each individual VLAN is modeled as a virtual network interface.
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This means that there is an ethernet network interface that corresponds to
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a real physical ethernet port in the system. A virtual network interface is
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created for each VLAN, and this virtual network interface connects to the
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real network interface. This is similar to how Linux implements VLANs. The
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*eth0* is the real network interface and *vlan0* is a virtual network interface
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that is run on top of *eth0*.
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VLAN support must be enabled at compile time by setting option
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:option:`CONFIG_NET_VLAN` and also setting option
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:option:`CONFIG_NET_VLAN_COUNT` to reflect how many network interfaces there
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will be in the system. For example, if there is one network interface without
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VLAN support, and two with VLAN support, the :option:`CONFIG_NET_VLAN_COUNT`
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should be set to 3.
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Even if VLAN is enabled in a :file:`prj.conf` file, the VLAN needs to be
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activated at runtime by the application. The VLAN API provides a
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:cpp:func:`net_eth_vlan_enable()` function to do that. The application needs
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to give the network interface and desired VLAN tag as a parameter to that
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function. The VLAN tagging for a given network interface can be disabled by a
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:cpp:func:`net_eth_vlan_disable()` function. The application needs to configure
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the VLAN network interface itself, such as setting the IP address, etc.
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See also the :ref:`vlan-sample` VLAN sample application for API usage
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example. The source code for that sample application can be found at
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:file:`samples/net/vlan`.
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The net-shell module contains *net vlan add* and *net vlan del* commands
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that can be used to enable or disable VLAN tags for a given network interface.
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See the `IEEE 802.1Q spec`_ for more information about ethernet VLANs.
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.. _IEEE 802.1Q spec: https://ieeexplore.ieee.org/document/6991462/
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