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Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
—
Release 8.1
78-15486-01
Chapter 7 Configuring Spanning Tree
Configuring MST
Console> (enable) show spantree mst 6/1
Edge Port: No, (Configured) Default
Link Type: P2P, (Configured) Auto
Port Guard: Default
Boundary: Yes (PVST)
Inst State Role Cost Prio VLANs
---- ------------- ---- --------- ----
-----------------------------------
0 forwarding ROOT 20000 32 1
1 forwarding BDRY 20000 32 2-20
2 forwarding BDRY 20000 32 21-30
3 forwarding BDRY 20000 32 31-40
4 forwarding BDRY 20000 32 41-50
Console> (enable)
Console> (enable)
Console> (enable) show spantree mst config
Current (NVRAM) MST Region Configuration:
Configuration Name:cisco Revision:1
Instance VLANs
-------- --------------------------------------------------------------
IST 1,51-4094
1 2-20
2 21-30
3 31-40
4 41-50
5 -
6 -
7 -
8 -
9 -
10 -
11 -
12 -
13 -
14 -
15 -
=======================================================================
Console> (enable)
Configuring the MST Bridge ID Priority
You can set the bridge ID priority for an MST instance when the switch is in MST mode. The switch
combines the bridge priority value with the system ID extension (the ID of the MST instance) to create
the bridge ID priority. You can set 16 possible bridge priority values: 0, 4096, 8192, 12,288, 16,384,
20,480, 24,576, 28,672, 32,768, 36,864, 40,960, 45,056, 49,152, 53,248, 57,344, and 61,440.
To configure the bridge ID priority for an MST instance, perform this task in privileged mode:
The example shows how to configure the bridge ID priority for an MST instance:
Console> (enable) set spantree priority 8192 mst 3
MST Spantree 3 bridge priority set to 8192.
Console> (enable)
Task
Command
Step 1
Configure the bridge ID priority for an
MST instance.
set spantree priority bridge_priority mst [instance]
Step 2
Verify the bridge ID priority.
show spantree mst [instance | mod/port]
