Nortel BayStack 450-24T - Figure D-5. LEC Vports with Spanning Tree Enabled (1; Spanning Tree on LEC Vports

ATM Overview
309978-D Rev 01 D-11
Spanning Tree on LEC VPorts
The default STP setting for your BayStack 450-2M3/2S3 MDA’s LEC VPorts is
Normal Learning. Because BayStack 450 switches (software version V3.1, and
earlier) do not support multiple STPs, you may have to disable STP on all LEC
VPorts.
Figure D-5 shows possible consequences of not disabling the STP when
using the BayStack 450-2M3/2S3 MDA.
Figure D-5. LEC VPorts with Spanning Tree Enabled (1 of 2)
As shown in Figure D-5, there are four virtual parallel links between the two
BayStack 450-2M3/2S3 MDAs. Each link consists of a LEC VPort on each side
on the same ELAN. Because STP is enabled for the four LEC VPorts, three of the
LEC VPorts are in the Blocking state (based on the spanning tree algorithm).
PC1
PC2
BS45091A
BayStack 450
BayStack 450
Legend
Blocking
Forwarding
450-2M3/2S3 MDA
LEC 2/ ELAN 2/ Vport 26
LEC 3/ ELAN 3/ Vport 27
LEC 1/ ELAN 1/ Vport 25
LEC 4/ ELAN 4/ Vport 28
450-2M3/2S3 MDA
ATM Network
LEC 2/ ELAN 2/ Vport 26
LEC 3/ ELAN 3/ Vport 27
LEC 1/ ELAN 1/ Vport 25
LEC 4/ ELAN 4/ Vport 28