Command:

show spantree

Mode:

Switch> (enable)


Syntax:

show spantree [vlan | mod/port] [active]


Syntax Description:

vlan

(Optional) Variable that specifies the number of the VLAN.

mod/port

(Optional) Variable that specifies the number of the module and the port on the module.

active

(Optional) Keyword that displays only the active ports.


Command Description:

Use the show spantree command to display spanning tree information for a VLAN. If the VLAN number is not specified, the default is VLAN 1.


Examples:

This example shows how to display the spanning tree configuration for VLAN 64:

Console> show spantree 64

VLAN 64

Spanning tree enabled

Designated Root             00-10-79-57-88-00
Designated Root Priority    8191
Designated Root Cost        3061
Designated Root Port        6/48
Root Max Age   20 sec    Hello Time 2  sec   Forward Delay 15 sec

Bridge ID MAC ADDR          00-50-3e-8f-8c-00
Bridge ID Priority          4160 (bridge priority: 4096, sys ID ext: 64)
Bridge Max Age 6  sec    Hello Time 2  sec   Forward Delay 4  sec

Port,Vlan Vlan  Port-State     Cost   Priority  Fast-Start  Group-method
--------- ----  -------------  -----  --------  ----------  ------------
 1003     1005  inactive          80        32   disabled
Console>
 

This example shows how to display only the active ports:

Console> show spantree active

VLAN 1
Spanning tree enabled
Spanning tree type          ieee

Designated Root             00-60-70-4c-70-00
Designated Root Priority    32768
Designated Root Cost        19
Designated Root Port        1/1
Root Max Age   20 sec    Hello Time 2  sec   Forward Delay 15 sec

Bridge ID MAC ADDR          00-e0-1e-9b-2e-00
Bridge ID Priority          32768
Bridge Max Age 20 sec    Hello Time 2  sec   Forward Delay 15 sec

Port      Vlan  Port-State     Cost   Priority  Fast-Start  Group-Method
--------- ----  -------------  -----  --------  ----------  ------------
 1/1      1     forwarding        19        32   disabled
 3/1-2    1     forwarding        19        32   disabled    redundancy
 

The table below describes the possible fields in the show spantree command output.


Table: show spantree Command Output Fields

 
Field Description

VLAN

VLAN for which spanning tree information is shown

Spanning tree

Status of whether Spanning Tree Protocol is enabled or disabled

Designated Root

MAC address of the designated spanning tree root bridge

Designated Root Priority

Priority of the designated root bridge

Designated Root Cost

Total path cost to reach the root

Designated Root Port

Port through which the root bridge can be reached (shown only on nonroot bridges)

Root Max Age

Amount of time a BPDU packet should be considered valid

Hello Time

Number of times the root bridge sends BPDUs

Forward Delay

Amount of time the port spends in listening or learning mode

Bridge ID MAC ADDR

Bridge MAC address

Bridge ID Priority

Bridge priority

Bridge Max Age

Bridge maximum age

Hello Time

Amount of time the bridge sends BPDUs

Forward Delay

Amount of time the bridge spends in listening or learning mode

Port

Port number

Vlan

VLAN to which the port belongs

Port-State

Spanning tree port state (disabled, inactive, not-connected, blocking, listening, learning, forwarding, bridging, or type-pvid-inconsistent)

Cost

Cost associated with the port

Priority

Priority associated with the port

Fast-Start

Status of whether the port is configured to use the fast-start feature

Group-Method

How the multiple ports are treated (redundancy=dual PHY and FDDI; repeater=RSM; channel=Fast EtherChannel)


Misconceptions:

None

Related commands:
set spantree backbonefast
set spantree disable
set spantree enable
set spantree fwddelay
set spantree hello
set spantree maxage
set spantree portcost
set spantree portfast
set spantree portpri
set spantree portvlancost
set spantree portvlanpri
set spantree root
set spantree uplinkfast
show spantree backbonefast

� Cisco Systems, Inc. 2001, 2002, 2003
World Wide Education

Converted from CHM to HTML with chm2web Pro 2.85 (unicode)