Technical data

BLADE OS 5.1 Application Guide
BMD00136, November 2009 Chapter 3: VLANs
 53
Figure 5 802.1Q tag assignment
As shown in Figure 6, the tagged packet remains unchanged as it leaves the switch through port 5,
which is configured as a tagged member of VLAN 2. However, the tagged packet is stripped
(untagged) as it leaves the switch through port 7, which is configured as an untagged member of
VLAN 2.
Figure 6 802.1Q tagging (after 802.1Q tag assignment)
Port 6
DASATagDataCRC
Tagged packet
BS45013A
Port 7 Port 8
Port 1
Port 4 Port 5
Port 2 Port 3
802.1Q Switch
PVID = 2
Untagged member
of VLAN 2
Tagged member
of VLAN 2
B e f o r e
BS45014A
Port 6 Port 7 Port 8
Port 1
Port 4 Port 5
Port 2 Port 3
802.1Q Switch
Key
Priority
CFI
VID
- User_priority
- Canonical format indicator
- VLAN identifier
PVID = 2
Tagged member
of VLAN 2
Untagged member
of VLAN 2
After
DA
SA
Data
CRC*
(*Recalculated)
Outgoing
untagged packet
changed
(tag removed)
DASADataCRC Tag
VID = 2Priority
16 bits 3 bits 1 bit 12 bits
8100 CFI