139Figure 39 VLAN tag placement and formatA VLAN tag includes the following fields:• TPID—16-bit tag protocol identifier that indicates whether a frame is VLAN-tagged. By default, theTPID value is 0x8100, indicating that the frame is VLAN-tagged. However, device vendors can setTPID to different values. For compatibility with neighbor devices, configure the TPID value on thedevice to be the same as the neighbor device.• Priority—3-bit long 802.1p priority of the frame. For more information, see ACL and QoSConfiguration Guide.• CFI—1-bit long canonical format indicator that indicates whether the MAC addresses areencapsulated in the standard format when packets are transmitted across different media. Value 0(the default) indicates that the MAC addresses are encapsulated in the standard format. Value 1indicates that MAC addresses are encapsulated in a non-standard format. The CFI is 0 in Ethernet.• VLAN ID—12-bit long, identifies the VLAN that the frame belongs to. The VLAN ID range is 0 to4095. VLAN IDs 0 and 4095 are reserved, and VLAN IDs 1 to 4094 are user configurable.A network device handles an incoming frame depending on whether the frame is VLAN tagged and thevalue of the VLAN tag. For more information, see "Introduction to port-based VLAN."Ethernet supports encapsulation formats Ethernet II, 802.3/802.2 LLC, 802.3/802.2 SNAP, and 802.3raw. The Ethernet II encapsulation format is used here. For how the VLAN tag fields are added to framesencapsulated in the other formats for VLAN identification, see related protocols and standards.For a frame with multiple VLAN tags, the device handles it according to its outer-most VLAN tag andtransmits its inner VLAN tags as payload.Protocols and standardsIEEE 802.1Q, IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local AreaNetworksConfiguring basic VLAN settingsStep Command Remarks1. Enter system view. system-view N/A2. (Optional.) Create aVLAN and enter its view,or create a list of VLANs.vlan { vlan-id1 [ to vlan-id2 ] |all }By default, only the system default VLAN(VLAN 1) exists.3. Enter VLAN view. vlan vlan-id To configure a VLAN after you create a listof VLANs, you must perform this step.4. Configure a name forthe VLAN. name textBy default, VLAN names are in the formatVLAN vlan-id. For example, the name ofVLAN 100 is VLAN 0100 by default.
