Nortel business policy switch 2000, Руководство пользователя

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114 Chapter 2 Network configuration
208700-C
Figure 19 Port-based VLAN assignment
As shown in Figure 20 , 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 20 802.1Q tagging (after port-based VLAN assignment)
In Figure 21 , untagged incoming packets are assigned to VLAN 3 (policy
VLAN = 3, PVID = 2). Port 5 is configured as a tagged member of VLAN 3,
and port 7 is configured as an untagged member of VLAN 3.
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 member
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