C H A P T E R 2 Intel
®
Express 530T Switch Users Guide
18
IEEE 802.1Q (tag)-based VLANs
The second type of VLAN supported by the 530T switch is based on the
IEEE 802.1Q specification. The specification provides a uniform way for
creating VLANs within a network and allows the creation of a VLAN
that can also span across the network. Until recently, VLAN
implementation was vendor specific so it was not possible to create a
VLAN across devices from different vendors.
The 802.1Q VLAN works by using a tag added to the Ethernet frames.
The tag contains a VLAN Identifier (VID) that identifies the frame as
belonging to a specific VLAN. These tags allow switches that support the
802.1Q specification to segregate traffic between devices and
communicate a device’s VLAN association across switches.
There are multiple advantages to implementing 802.1Q VLANs. First, it
helps to contain broadcast and multicast traffic across the switch thus
improving performance. Second, ports can belong to more than one
VLAN. Third, VLANs can span multiple switches that support the
802.1Q specification. Finally, it can provide security and improve
performance by logically isolating users and grouping them together.
The 530T switch supports up to 2047 tag-based VLANs.
A logical grouping can be mapped to a work group. For example, you can
create a VLAN that groups all the users from the engineering department
into one VLAN. A benefit of this logical grouping is that it can improve
performance by cutting down traffic that belongs to a different logical
group (for example, marketing), improve security (engineering can’t see
marketing), and ease moves since the user doesn’t have to be physically
located in the same group to participate in the VLAN.
When a 530T switch is stacked with one or more 535T switches, ports
from any/all of the switches can be members of a tag-based VLAN.
NOTE
When a 530T is stacked with
one or more 535T switches,
ports from any/all of the
switches can be members of
each VLAN.
VLAN 1:
Engineering
Server and printer
are members of both
VLANs
VLAN 2:
Manufacturing
VLAN 1 computers
can't see VLAN 2
computers
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Link\Activity
Link = Solid Green
Activity = Blinking Green
Port 1
Port 2
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10/100Base-T Module
Port 1
Port 2
Switch
Status
Status Link
Stacking
Module
Module A
Module A
Intel
®
Express 535T Switch
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Local
Management
(EIA 232)
Console: 9600-8-N-1
FlowCtrl=None
Link\Activity
Link = Solid Green
Activity = Blinking Green
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Switch
Status
Status Sw1
Sw2
Sw3
Matrix
Module
Status Port 1
Link/
Act
Port 2
Link/
Act
Module A
(Gigabit)
Intel
®
Express 530T Switch
530T
535T
530-Chapter2.fm Page 18 Monday, September 11, 2000 4:14 PM
