The VLAN tag (802.1Q protocol) is a 4B field in the Ethernet frame. It is inserted between the MAC address and EtherType/Length fields of the original frame.
The VLAN packet is defined by two main parameters:
| VLAN tag | – VLAN Identifier (VID) is also called “VLAN number”. It is 12 bits long so we can have up to 4096 VLANs (0x0000 and 0xFFF values are reserved). |
| Priority Code Point (PCP) | – a 3bit field which refers to the IEEE 802.1p priority. It indicates the frame priority level. Possible values are from 0 (best effort) to 7 (highest priority); 1 represents the lowest priority. These values can be used to prioritize different traffic classes (voice, data, …). |
See the following example:
As you can see in Fig. 2.1, “VLAN diagram”, we have individual VLANs for Management and two distinct technologies, each with its own IP subnet.
![[Note]](/images/radost/images/icons/note.png){kind=icon} | Note |
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You can combine the VLAN feature with a TCP proxy and Terminal Servers. See the respective help in the RipEX web interface for details. |