Nortel business policy switch 2000, User Manual

Page: 117 / 412

Chapter 2 Network configuration 117
Using the Business Policy Switch 2000 Version 2.0
As shown in Figure 24 , 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 24 802.1Q tagging (after 802.1Q tag assignment)
VLANs spanning multiple switches
You can use VLANs to segment a network within a switch. When you connect
multiple switches, it is possible to connect users of one VLAN with users of that
same VLAN in another switch. However, the configuration guidelines depend on
whether both switches support 802.1Q tagging.
With 802.1Q tagging enabled on a port for a VLAN, all frames leaving the port for
that VLAN are
marked as belonging to that specific VLAN. You can assign
specific switch ports as members of one or more VLANs that span multiple
switches, without interfering with the Spanning Tree Protocol.
Refer to Chapter 1 for additional guidelines on configuring VLANs and spanning
tree groups.
BS45014A
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
changed
(tag removed)
DA SA Data CRC Tag
VID = 2 Priority
16 bits 3 bits 1 bit 12 bits
8100 CFI