Per-VLAN Spanning Tree Plus (PVST+) | 403
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Per-VLAN Spanning Tree Plus (PVST+)
Overview
Per-VLAN spanning tree plus (PVST+) is a variation of spanning tree—developed by a third party—that 
allows you to configure a separate spanning tree instance for each VLAN (Figure 23-1). For more 
information about spanning tree, refer to Spanning Tree Protocol (STP). 
Figure 23-1.  Per-VLAN Spanning Tree 
R2
R3
R1
2/32
1/22
1/32
2/12
3/22
3/12
STI 3: VLAN 300
STI 1: VLAN 100
STI 2: VLAN 200STI 2: VLAN 200
Forwarding
X
X
X
STI 1/2/3 root
Blocking