Reference Guide

792 | Per-VLAN Spanning Tree Plus
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Figure 43-3. PVST+ with Extend System ID
Displaying STP Guard Configuration
To verify the STP guard configured on PVST interfaces, enter the show spanning-tree pvst [vlan vlan-id]
guard command. Refer to the Spanning Tree Protocol chapter for information on how to configure and use
the STP root guard, loop guard, and BPDU guard features.
The following output example shows an example for VLAN 5 in a PVST network in which:
• Root guard is enabled on a port that is in a root-inconsistent state.
• Loop guard is enabled on a port that is in a forwarding state.
• BPDU guard is enabled on a port that is shut down.
FTOS#show spanning-tree pvst vlan 5 guard
Interface
Name Instance Sts Guard type
--------- -------- --------- ----------
Gi 0/1 5 INCON(Root) Root
Gi 0/2 5 FWD Loop
Gi 0/3 5 EDS(shut) Bpdu
Task Command Syntax Command Mode
Augment the Bridge ID with the VLAN ID. extend system-id PROTOCOL PVST
FTOS(conf-pvst)#do show spanning-tree pvst vlan 5 brief
VLAN 5
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 32773, Address 0001.e832.73f7
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 32773 (priority 32768 sys-id-ext 5), Address 0001.e832.73f7
We are the root of Vlan 5
Configured hello time 2, max age 20, forward delay 15
...
VLAN unaware
Hub
Dell Force10 System
P1
untagged in VLAN 10
P2
untagged in VLAN 20
X
moves to blocking unless
Extended System ID is
enabled