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52
Enhanced Features
WAGO-ETHERNET-Zubehör 852
852-1305 8/4-Port 100BASE-T/1000BASE-SX/LX
Manual
1.1.0
802.1Q Tag:
2 bytes
2 bytes
Tag Protocol Identifier (TPID)
Tag Control Information (TCI)
16 bits
3 bits
1 bits
12 bits
TPID (0x8100)
Priority CFI
VID
•
TPID (“
T
ag
P
rotocol
Id
entifier”)
A 16-bit field is set to the value of 0x8100 to identify the frame as an “IEEE
802.1Q Tag Frame”.
•
TCI (“
T
ag
C
ontrol
I
nformation”)
- PCP (“
P
riority
C
ode
P
oint”)
A 3-bit field that refers to the IEEE 802.1p priority. It indicates the
frame priority level from 0 (lowest) to 7 (highest), which can be used to
prioritize different classes of traffic (voice, video, data, etc.).
- CFI (“
C
anonical
F
ormat
I
ndicator”)
A 1-bit field. If the value of this field is 1, the MAC address is in non-
canonical format. If the value is 0, the MAC address is in canonical
format. It is always set to 0 for ETHERNET switches. CFI is used for
compatibility between ETHERNET and “Token Ring” networks. If a
frame received at an ETHERNET port has a CFI of 1, the frame should
not be output to an untagged port.
- VID (“
V
LAN
Id
entifier”)
A 12-bit field specifying the VLAN to which the frame belongs. A
value of 0 means 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”. A hexadecimal value of 0xFFF is reserved for
implementation purposes. All other values may be used as “VLAN
Identifiers”, allowing support for up to 4094 VLANs. On “Bridges”,
VLAN 1 is often reserved for management.