The frame decoder recognizes an inner VLAN-tagged frame if the TPID (tag protocol identifier) is 0x8100, 0x88A8 or equal to an alternative TPID determined by the AltTPID parameter in the ntservice.ini file (see DN-0449), and one of these conditions is met:
- The tunnel type is GRE_v0, and the GTP Protocol Type field is 0x6558 (NVGRE).
- The tunnel type is EtherIP.
A maximum of 3 VLANs are supported.
Note: VLAN tags are only recognized if they appear right after the layer 2 source MAC address.
The length of the VLAN field depends on the number of VLANs. The possible values are 0, 4, 8 and 12 bytes.