Example Application of MSTP Reconvergence

The following example shows the running configuration file before and after deleting a VLAN from the configuration. The VLAN to MSTI mapping is retained in the running configuration, even after the VLAN is deleted.

device(config-vlan-20)# show run
  
Current configuration:
!
ver 04.2.00bT3e1
!
!
vlan 1 name DEFAULT-VLAN by port
 no spanning-tree
!
vlan 10 by port
 tagged ethe 1/1/1 to 1/1/2
 no spanning tree
!
vlan 20 by port                       <----- VLAN 20 configuration
 
 tagged ethe 1/1/1 to 1/1/2 
 no spanning-tree
!
mstp scope all
mstp instance 0 vlan 1
mstp instance 1 vlan 20  
mstp start
some lines omitted for brevity... device(config-vlan-20)#no vlan 20   <----- VLAN 20 deleted 
device(config-vlan-20)#show run
  
Current configuration:
!
ver 04.2.00bT3e1
!
!
vlan 1 name DEFAULT-VLAN by port
 no spanning-tree
!
vlan 10 by port
 tagged ethe 1/1/1 to 1/1/2 
 no spanning-tree
!
mstp scope all
mstp instance 0 vlan 1
mstp instance 1 vlan 10
mstp instance 1 vlan 20               <----- VLAN to MSTI mapping kept in 
mstp start                                   running configuration, even though 
                                             VLAN 20 was deleted 

some lines omitted for brevity...