Intel 460T manual Spanning Tree and VLANs, Switch

C H A P T E R 2 Intel Express 460T Standalone Switch Users Guide

On the 460T switch, overlapping VLANs can be supported by using 802.1Q- capable devices. However, for non-802.1Q-capable devices, overlapping VLANs can be supported by implementing an asymmetric VLAN on the switch. An asymmetric VLAN is a type of 802.1Q configuration where endstations send traffic on one VLAN and receive traffic on another VLAN. The 460T switch supports asymmetric VLANs.

For more information about asymmetric VLANs, see http://support.intel.com /support or see IEEE 802.1Q Specification Annex B.1.3.

Spanning Tree and VLANs

The 460T supports the Spanning Tree Protocol across the entire switch, not per VLAN. If a loop occurs in a VLAN the port is disabled and all VLAN traffic over that port is blocked.

The following diagram shows an example. 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 GVRP(GARPVLAN Registration Protocol) to work properly.

Intel® Express 460T Standalone Switch

Module A

Switch 1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

ENG_VLAN ports 1-8

crossover

connecting ENG_VLANs

MKT_VLAN ports 17-24

Spanning Tree disables the redundant crossover breaking the connection between the MKT_VLANs.

Switch 2

	Intel® Express 460T Standalone Switch							Module A
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24

ENG_VLAN
	MKT_VLAN
ports 1-8
	ports 17-24

20