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-rw-r--r-- | Documentation/networking/bridge.rst | 29 |
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diff --git a/Documentation/networking/bridge.rst b/Documentation/networking/bridge.rst index c14410008ddf..97936b9564fd 100644 --- a/Documentation/networking/bridge.rst +++ b/Documentation/networking/bridge.rst @@ -148,6 +148,35 @@ called by the kernel when STP is enabled/disabled on a bridge stp_state <0|1>``). The kernel enables user_stp mode if that command returns 0, or enables kernel_stp mode if that command returns any other value. +VLAN +==== + +A LAN (Local Area Network) is a network that covers a small geographic area, +typically within a single building or a campus. LANs are used to connect +computers, servers, printers, and other networked devices within a localized +area. LANs can be wired (using Ethernet cables) or wireless (using Wi-Fi). + +A VLAN (Virtual Local Area Network) is a logical segmentation of a physical +network into multiple isolated broadcast domains. VLANs are used to divide +a single physical LAN into multiple virtual LANs, allowing different groups of +devices to communicate as if they were on separate physical networks. + +Typically there are two VLAN implementations, IEEE 802.1Q and IEEE 802.1ad +(also known as QinQ). IEEE 802.1Q is a standard for VLAN tagging in Ethernet +networks. It allows network administrators to create logical VLANs on a +physical network and tag Ethernet frames with VLAN information, which is +called *VLAN-tagged frames*. IEEE 802.1ad, commonly known as QinQ or Double +VLAN, is an extension of the IEEE 802.1Q standard. QinQ allows for the +stacking of multiple VLAN tags within a single Ethernet frame. The Linux +bridge supports both the IEEE 802.1Q and `802.1AD +<https://lore.kernel.org/netdev/1402401565-15423-1-git-send-email-makita.toshiaki@lab.ntt.co.jp/>`_ +protocol for VLAN tagging. + +`VLAN filtering <https://lore.kernel.org/netdev/1360792820-14116-1-git-send-email-vyasevic@redhat.com/>`_ +on a bridge is disabled by default. After enabling VLAN filtering on a bridge, +it will start forwarding frames to appropriate destinations based on their +destination MAC address and VLAN tag (both must match). + FAQ === |