RDL-3000
User Manual
70-00158-01-DRAFT
Proprietary Redline Communications © 2010
Page
137
of 142
November 25, 2010
8.2.3
VLAN (802.1Q) Fields
The tag is located at the position used for the EtherType/Size field in untagged frames.
Table 44
:
Spec. - 802.1Q Tag Field
16 bits
3 bits
1 bit
12 bits
TPID
PCP
CFI
VID
Tag Protocol Identifier (TPID)
: 16-bit field set to 0x8100 identifies the IEEE 802.1Q-
tagged frame. Located at the EtherType/Size field position (untagged frame).
Priority Code Point (PCP)
: 3-bit field IEEE 802.1p priority bits from 0 (lowest) to 7
(highest).
Canonical Format Indicator (CFI)
: 1-bit field. Value 0 indicates MAC address is in
canonical format (e.g., for Ethernet switches).
VLAN Identifier (VID)
: 12-bit field specifying the VLAN. Value 0 indicates the frame
does not belong to any VLAN and the 802.1Q tag is specifying only a priority
.
VLAN
value may be 1 to 4094.