198Step Command Remarks3. Configure the port link type. port link-type { hybrid | trunk } By default, the link type ofports is access.4. Configure the port to allowpackets from its PVID and thetransparent VLANs to passthrough.• For hybrid ports:port hybrid vlan vlan-id-list { tagged| untagged }• For trunk ports:port trunk permit vlan { vlan-id-list |all }By default, trunk ports allowonly packets from VLAN 1 topass through. Hybrid portsallow only packets fromVLAN 1 to pass throughuntagged.5. Enable QinQ on the port. qinq enable By default, QinQ is disabled.6. Specify transparent VLANs. qinq transparent-vlan vlan-listBy default, transparenttransmission is not configuredfor any VLANs on a port.Configuring the TPID in VLAN tagsTPID identifies a frame as an 802.1Q tagged frame. On the device, the TPID in the 802.1Q tag addedon a QinQ-enabled port is 0x8100 by default, in compliance with IEEE 802.1Q. However, the TPID valuevaries with vendors. In a multi-vendor network, you must make sure the TPID setting is the same across alldevices so 802.1Q tagged frames can be identified correctly.TPID settings include CVLAN TPID and SVLAN TPID.A QinQ-enabled port uses the CLAN TPID to match incoming tagged frames. An incoming frame ishandled as an untagged frame if its TPID is different from the CVLAN TPID.A service provider-side port uses the SVLAN TPID to replace the TPID in outgoing frames' SVLAN tags, inaddition to matching incoming tagged frames. SVLAN TPIDs are configurable on a per-port basis.For example, the PE device is connected to a customer device that uses the TPID 0x8200 and to aprovider device that uses the TPID 0x9100. To be compatible with these devices, you must configure0x8200 and 0x9100 as the CVLAN TPID and SVLAN TPID, respectively, so the devices can correctlyidentify tagged frames.The TPID in a tagged Ethernet frame is in the same position as the EtherType field in an untagged Ethernetframe. To ensure correct packet type identification, do not set the TPID value to any of the values listedin Table 12.Table 12 Reserved EtherType valuesProtocol type ValueARP 0x0806PUP 0x0200RARP 0x8035IP 0x0800IPv6 0x86DDPPPoE 0x8863/0x8864MPLS 0x8847/0x8848
