Nortel Networks 450 - Manual (Page 61)

BayStack 450 10/100/1000 Series Switches
302401-D Rev 00 1-35
In Figure 1-17 , untagged incoming packets are assigned directly to VLAN 2
(PVID = 2). Port 5 is configured as a tagged member of VLAN 2, and port 7 is
configured as an untagged member of VLAN 2.
Figure 1-17. 802.1Q Tagging (1 of 4)
As shown in Figure 1-18 , the untagged packet is marked (tagged) as it leaves the
switch through port 5, which is configured as a tagged member of VLAN 2. The
untagged packet remains unchanged as it leaves the switch through port 7, which
is configured as an untagged member of VLAN 2.
Figure 1-18. 802.1Q Tagging (2 of 4)
Port 6
DA SA Data CRC
BS45011A
Port 7 Port 8
Port 1
Po
rt
4
Po
rt
5
Port 2 Port 3
802.1Q Switch
PVID = 2
Untagged packet
Untagged member
of VLAN 2
Tagged member
of VLAN 2
Before
BS45012A
Port 6 Port 7 Port 8
Port 1
Po
rt
4
Po
rt
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 memeber
of VLAN 2
After
DA
SA
Data
CRC
(*Recalculated)
Outgoing
untagged packet
(unchanged)
DA SA Data CRC* Tag
VID = 2 Priority
16 bits 3 bits 1 bits 12 bits
8100 CFI
kombk.book Page 35 Tuesday, June 29, 1999 3:25 PM