Packet Ethernet1QTag

File: src/inet/linklayer/ethernet/EtherFrame.msg

C++ definition

Ethernet 802.1Q Tag.

Usage diagram:

The following diagram shows usage relationships between types. Unresolved types are missing from the diagram.

Inheritance diagram:

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Fields:

Name	Type	Description
pcp	uint8_t	Priority Code Point (PCP): a 3-bit field which refers to the IEEE 802.1p priority. It indicates the frame priority level. Values are from 0 (best effort) to 7 (highest); 1 represents the lowest priority.
de	bool	Drop Eligible (DE): a 1-bit field. May be used separately or in conjunction with PCP to indicate frames eligible to be dropped in the presence of congestion.
VID	short	VLAN Identifier (VID): a 12-bit field specifying the VLAN to which the frame belongs. The hexadecimal values of 0x000 and 0xFFF are reserved. All other values may be used as VLAN identifiers, allowing up to 4,094 VLANs. The reserved value 0x000 indicates that the frame does not belong to any VLAN; in this case, the 802.1Q tag specifies only a priority and is referred to as a priority tag. On bridges, VLAN 1 (the default VLAN ID) is often reserved for a management VLAN; this is vendor-specific.

Source code:

//
// Ethernet 802.1Q Tag.
//
packet Ethernet1QTag
{
    uint8_t pcp;    // Priority Code Point (PCP): a 3-bit field which refers to the IEEE 802.1p priority. It indicates the frame priority level.
                    // Values are from 0 (best effort) to 7 (highest); 1 represents the lowest priority.
    bool de;        // Drop Eligible (DE): a 1-bit field. May be used separately or in conjunction with PCP to indicate frames eligible to be dropped in the presence of congestion.
    short VID = 0;   // VLAN Identifier (VID): a 12-bit field specifying the VLAN to which the frame belongs.
                    // The hexadecimal values of 0x000 and 0xFFF are reserved. All other values may be used as VLAN identifiers, allowing up to 4,094 VLANs.
                    // The reserved value 0x000 indicates that the frame does not belong to any VLAN; in this case,
                    // the 802.1Q tag specifies only a priority and is referred to as a priority tag. On bridges,
                    // VLAN 1 (the default VLAN ID) is often reserved for a management VLAN; this is vendor-specific.
}