show mstp

Displays the Multiple Spanning Tree Protocol (MSTP) information.
Syntax
show mstp { [ detail ] mstp-id | configuration }
Parameters
detail
Displays detailed MSTP information for the specified ID.
mstp-id
Displays the MSTP information for a specific ID.
configuration
Displays MSTP configuration information.
Modes

User EXEC mode

The show mstp command can display the following information:

Output field Description
MSTP Instance The ID of the MSTP instance for which statistics are being displayed. For the CIST, this number is 0.
VLANs The number of VLANs that are included in this instance of MSTP. For the CIST, this number will always be 1.
Bridge Identifier The MAC address of the bridge.
Bridge MaxAge sec Displays the configured maximum age.
Bridge Hello sec Displays the configured Hello variable.
Bridge FwdDly sec Displays the configured FwdDly variable.
Bridge Hop cnt Displays the configured Max Hop count variable.
Root MaxAge sec The maximum age configured on the root bridge.
Root Hello sec The Hello interval configured on the root bridge.
Root FwdDly sec The FwdDly interval configured on the root bridge.
Root Hop Cnt The maximum hop count left from the root bridge.
Root Bridge The bridge identifier of the root bridge.
ExtPath Cost The configured path cost on a link connected to this port to an external MSTP region.
Regional Root Bridge The MAC address of the root bridge for the local region.
IntPath Cost The configured path cost on a link connected to this port within the internal MSTP region.
Designated Bridge The MAC address of the bridge that sent the best BPDU that was received on this port.
Root Port The port indicating the shortest path to the root; set to "Root" if this bridge is the root bridge.
Port Num The port number of the interface.
Pri Cost The configured priority of the port. The default is 128.
PortPath Cost The configured or auto-detected path cost for the port.
P2P Mac Indicates if the port is configured with a point-to-point link:
  • T = The port is configured in a point-to-point link.
  • F = The port is not configured in a point-to-point link.
Edge Indicates if the port is configured as an operational edge port:
  • T = Indicates that the port is defined as an edge port.
  • F = Indicates that the port is not defined as an edge port.
Role State The port current spanning tree state. A port can have one of the following states:
  • Forwarding
  • Discarding
  • Learning
  • Disabled
Designated Cost The port path cost to the root bridge.
Max Hop cnt The maximum hop count configured for this instance.
Examples

The following example displays MSTP information for a specified MSTP instance. 

device# show mstp 1
MSTP Instance 1 - VLANs: 2
----------------------------------------------------------------------------------
Bridge           Bridge Bridge Bridge Bridge Root   Root  Root   Root
Identifier       MaxAge Hello  FwdDly Hop    MaxAge Hello FwdDly Hop
hex              sec    sec    sec    cnt    sec    sec   sec    cnt
8000000cdb80af01 20     2      15     20     20     2     15     19
Root             ExtPath   RegionalRoot     IntPath   Designated       Root
Bridge           Cost      Bridge           Cost      Bridge           Port
hex                        hex                        hex
8000000480bb9876 2000      8000000cdb80af01 0         8000000480bb9876 3/1/1
Port    Pri PortPath  P2P Edge Role       State      Designa-  Designated
Num         Cost      Mac Port                       ted cost  bridge
3/1/1   128 2000      T   F    ROOT       FORWARDING 0         8000000480bb9876

The following example displays detailed MSTP information. 

device# show mstp detail
MSTP Instance 0 (CIST) - VLANs: 1 
----------------------------------------------------------------------------
    Bridge: 800000a0c9c002a0 [Priority 32768, SysId 0, Mac 00a0c9c002a0]
  FwdDelay 15, HelloTime 2, MaxHops 20, TxHoldCount 6, ForceVersion 3
Number of topology changes: 20
Last topology change occured 6 second(s)  ago on lg40

Port 1/1/1 - Role: DESIGNATED - State: FORWARDING
  PathCost 20000, Priority 128, OperEdge F, OperPt2PtMac F, rcvdInternal F, Boundary F
  Designated   - Root 800000a0c9c002a0, RegionalRoot 800000a0c9c002a0,
                 Bridge 800000a0c9c002a0, ExtCost 0, IntCost 0
  ActiveTimers - helloWhen 2
  MachineState - PRX-DISCARD, PTX-IDLE, PPM-SENDING_RSTP, PIM-CURRENT
                 PRT-ACTIVE_PORT, PST-FORWARDING, TCM-ACTIVE
  BPDUs 	- Rcvd MST 0, RST 0, Config 0, TCN 0
                 Sent MST 129, RST 0, Config 0, TCN 0

The following example displays MSTP configuration details. 

device# show mstp configuration
MSTP CONFIGURATION
------------------
Name : Reg1
Revision : 1
Version : 3 (MSTP mode)
Status : Started
Instanc  VLANs
-------- --------------
0        4093
Release version Command history
10.0.00 This command was modified to display more topology information details.
Parent topic: Show Commands