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Diffstat (limited to 'docs/interfaces/qinq.rst')
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diff --git a/docs/interfaces/qinq.rst b/docs/interfaces/qinq.rst index 12fbd47d..cc1812d0 100644 --- a/docs/interfaces/qinq.rst +++ b/docs/interfaces/qinq.rst @@ -1,16 +1,33 @@ -.. _interfaces-qinq: +.. _qinq-interface: -QinQ ----- +QinQ (802.1ad) +-------------- -QinQ (802.1ad_) — allows multiple VLAN tags to be inserted into a single frame. +IEEE 802.1ad was an Ethernet networking standard informally known as QinQ as +an amendment to IEEE standard :ref:`vlan-interface`. 802.1ad was incorporated +into the base 802.1q standard in 2011. The technique is also known as provider +bridging, Stacked VLANs, or simply QinQ or Q-in-Q. "Q-in-Q" can for supported +devices apply to C-tag stacking on C-tag (Ethernet Type = 0x8100). -QinQ can be used to tunnel vlans in a vlan. +The original 802.1q specification allows a single Virtual Local Area Network +(VLAN) header to be inserted into an Ethernet frame. QinQ allows multiple +VLAN tags to be inserted into a single frame, an essential capability for +implementing Metro Ethernet network topologies. Just as QinQ extends 802.1Q, +QinQ itself is extended by other Metro Ethernet protocols. -**vif-s** and **vif-c** stand for the ethertype tags that get set: +In a multiple VLAN header context, out of convenience the term "VLAN tag" or +just "tag" for short is often used in place of "802.1Q VLAN header". QinQ +allows multiple VLAN tags in an Ethernet frame; together these tags constitute +a tag stack. When used in the context of an Ethernet frame, a QinQ frame is a +frame that has 2 VLAN 802.1Q headers (double-tagged). -The inner tag is the tag which is closest to the payload portion of the frame; it is officially called C-TAG (Customer tag, with ethertype 0x8100). -The outer tag is the one closer/closest to the Ethernet header; its name is S-TAG (Service tag, ethertype 0x88a8). +In VyOS the terms **vif-s** and **vif-c** stand for the ethertype tags that +are used: + +The inner tag is the tag which is closest to the payload portion of the frame. +It is officially called C-TAG (customer tag, with ethertype 0x8100). The outer +tag is the one closer/closest to the Ethernet header, its name is S-TAG +(service tag with ethertype 0x88a8). Configuration commands: |