Disabling The Pvst+ Mode On A Vlan - Cisco WS-C6506 Software Manual

Configuring PVST+ on the Switch
Console> (enable) show config all
set spantree portcost
set spantree portcost
set spantree portcost
set spantree portpri
set spantree portvlanpri 2/1 0
set spantree portvlanpri 2/2 0
set spantree portvlanpri 2/48 0
set spantree portvlancost 2/1 cost 99
set spantree portvlancost 2/2 cost 99
set spantree portvlancost 2/3 cost 20000 1-5,12

Disabling the PVST+ Mode on a VLAN

When the switch is in PVST+ mode, you can disable spanning tree on individual VLANs or all VLANs.
When you disable spanning tree on a VLAN, the switch does not participate in spanning tree and any
BPDUs that are received in that VLAN are flooded on all ports.
We do not recommend disabling spanning tree, even in a topology that is free of physical loops. Spanning
Caution
tree serves as a safeguard against misconfigurations and cabling errors. Do not disable spanning tree in
a VLAN without ensuring that there are no physical loops present in the VLAN.
Do not disable spanning tree on a VLAN unless all switches or routers in the VLAN have spanning tree
Caution
disabled. You cannot disable spanning tree on some switches or routers in a VLAN and leave spanning
tree enabled on other switches or routers in the VLAN. If spanning tree remains enabled on the switches
and routers, they will have incomplete information about the physical topology of the network. This
situation may cause unexpected results.
To disable PVST+, perform this task in privileged mode:
Task
Disable PVST+ mode on a VLAN.
This example shows how to disable PVST+ on a VLAN:
Console> (enable) set spantree disable 4
Spantree 4 disabled.
Console> (enable)
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
7-32
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2/12,2/15 19
2/1-2,2/4-11,2/13-14,2/16-48 100
2/3 12
2/1-48 32
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Chapter 7 Configuring Spanning Tree
Command
set spantree disable vlans [all]
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