Spanning Tree And Vlans - Intel Express 530T User Manual

C H A P T E R
®
2 Using the Intel Express 530T Switch
On the 530T switch, overlapping VLANs can be supported through the
use of 802.1Q-capable devices. However, for non-802.1Q-capable
devices, overlapping VLANs can be supported by implementing an
asymmetric VLAN on the switch (see references below for more
information). An asymmetric VLAN is a type of 802.1Q configuration
where endstations send traffic on one VLAN and receive traffic on
another VLAN. The 530T switch can support asymmetric VLANs.
To learn more about asymmetric VLANs, see
http://support.intel.com/support or refer to IEEE 802.1Q Specification
Annex B.1.3.

Spanning Tree and VLANs

The 530T supports the Spanning Tree Protocol across the entire switch
(or stack of switches), not per VLAN. If a loop occurs in a VLAN the port
is disabled and all VLAN traffic over that port is blocked.
A good example of this can be seen below. Both Switch 1 and Switch 2
have two port-based VLANs configured. Crossover cables connect the
ENG_VLAN on Switch 1 to ENG_VLAN on and Switch 2. Crossover
cables also connect the MRKT_VLAN on Switch 1 to the
MRKT_VLAN on Switch 2. When Spanning Tree is enabled, the
redundant link between the MRKT_VLANs is blocked and those
VLANs can no longer communicate.
When the switch is running 802.1Q VLANs, Spanning Tree is required
for GARP VLAN Registration Protocol (GVRP) to work properly.
Matrix Module A
Intel ® Express 530T Switch Switch Module Status Sw1 Sw2 Sw3 (Gigabit) Status Port 1
Status
Local
Console: 9600-8-N-1
Management
FlowCtrl=None
(EIA 232)
Switch 1
Crossover connecting
ENG_VLANs
Switch 2
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
Port 2
Link/ Link/
Act Act
Link\Activity
Link = Solid Green
Activity = Blinking Green
1 3 5 7 9 11 13 15 17 19 21
2 4 6 8 10 12 14 16 18 20 22
ENG_VLAN
ports 1-8
Module A
® Port 1 Port 2
Intel Express 460T Standalone Switch
Status Link\Act\Coll Link\Act\Coll
MDI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
MDI-X
ENG_VLAN
ports 1-8
MKT_VLAN
ports 15-22
Spanning Tree disables
the redundant crossover,
breaking the connection
between the MKT_VLANs.
Status
Left
22 23 24 Link = Solid Green
Activity = Blinking Green
Collision = Blinking Orange
Right
10Mbps = Solid Orange
100Mbps = Off
MKT_VLAN
ports 17-24
19