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1 HundredGigE1/0/1 ROOT FORWARDING NONE
1 HundredGigE1/0/2 ALTE DISCARDING NONE
4 HundredGigE1/0/3 DESI FORWARDING NONE
# Display brief spanning tree information on Device D.
[DeviceD] display stp brief
MST ID Port Role STP State Protection
0 HundredGigE1/0/1 ROOT FORWARDING NONE
0 HundredGigE1/0/2 ALTE DISCARDING NONE
0 HundredGigE1/0/3 ALTE DISCARDING NONE
3 HundredGigE1/0/1 ROOT FORWARDING NONE
3 HundredGigE1/0/2 ALTE DISCARDING NONE
4 HundredGigE1/0/3 ROOT FORWARDING NONE
Based on the output, you can draw each MSTI mapped to each VLAN, as shown in
Figure 43 MSTIs mapped to different VLANs
PVST configuration example
Network requirements
As shown in
, Device A and Device B work at the distribution layer, and Device C and
Device D work at the access layer.
Configure PVST to meet the following requirements:
•
Frames of a VLAN are forwarded along the spanning trees of the VLAN.
•
VLAN 10, VLAN 20, and VLAN 30 are terminated on the distribution layer devices, and VLAN
40 is terminated on the access layer devices.
•
The root bridge of VLAN 10 and VLAN 20 is Device A.
•
The root bridge of VLAN 30 is Device B.
•
The root bridge of VLAN 40 is Device C.
A
B
A
B
C
D
C
B
C
MSTI 1 mapped to VLAN 10
A
D
D
Root bridge
Normal link
Blocked link
MSTI 3 mapped to VLAN 30
MSTI 0 mapped to VLAN 20
MSTI 4 mapped to VLAN 40