C_Tag - 802.1Q Customer VLAN Tag Type¶

pcapkit.protocols.link.c_tag.protocol contains C_Tag only, which implements the extractor for the 802.1Q Customer VLAN Tag Type (C-Tag) [*], EtherType 0x8100.

Its structure, and all of its parsing and construction, come from VLAN; this class adds only the tag’s own identity – name, alias, info_name, id() – and its registry index.

It has a package of its own, apart from S_Tag, since a package holds one protocol class, named after it, with only the framework bases in pcapkit.protocols.protocol exempt (#2529). The two tags are reached through different registry indices, 0x8100 against 0x88A8.

class pcapkit.protocols.link.c_tag.protocol.C_Tag(file=None, length=None, **kwargs)[source]¶

Bases: VLAN

This class implements 802.1Q Customer VLAN Tag Type.

Added in version 1.5.0: Takes over the customer tag from VLAN.

property name: Literal['802.1Q Customer VLAN Tag Type']¶: Name of current protocol.

property alias: Literal['802.1Q']¶: Acronym of corresponding protocol.

property info_name: Literal['c_tag']¶: Key name of the info dict.

classmethod id()[source]¶

Index ID of the protocol.

Return type:: tuple[Literal['C_Tag'], Literal['VLAN']]
Returns:: Index ID of the protocol. VLAN is retained alongside the class’s own name so that selecting VLAN tags by that name, e.g. pcapkit.extract(..., protocol='VLAN'), matches the customer tag; S_Tag carries the same alias.

classmethod __index__()[source]¶

Numeral registry index of the protocol.

Return type:: EtherType
Returns:: Numeral registry index of the protocol in IANA.

Footnotes