A Port can be one of the following types: Unaware, C-port, S-port, or S-custom-port where: - Unaware: all frames are classified to the Port VLAN ID and tags are not removed (default). - C-port: Customer port; with Customer tags (C-Tags), which use TPID 0x8100. - S-port: Service port; with Service tags (S-Tags), which use TPID 0x88A8 (IEEE 802.1ad). - S-custom-port: Custom Service port; with Service tags (S-Tags), which use a custom TPID assigned in tnSysVLANExtCustomSTag. For Customer tags and Service tags, both VLAN tags (tags with non-zero VID) and Priority tags (tags with VID = 0) are processed. The tag header is either retrieved from a tag in the incoming frame or from a default port-based tag header. The port-based tag header is configured in ieee8021QBridgePvid. For double-tagged frames, there is an option to use the inner tag instead of the outer tag. In addition to the tag header, the ingress port decides the number of VLAN tags to pop at egress. If the configured number of tags to pop is greater than the actual number of tags in the frame, the number is reduced to the actual number of tags in the frame.