Topology Change and Topology Change Detection
Set Spanning Tree Compatibility to STP
Restore Spanning Tree Compatibility
Restore the Default Bridge Priority
Configuring the STP Port Priority
Port Priority Configuration Topology Example
Restore the Default Port Priority
Configuring the Spanning Tree Link Type
Spanning Tree Link Type Overview
Configure the Interface Link Type
Restore the Default Interface Link Type
Configuring the Spanning Tree Portfast Port
Spanning Tree Portfast Port Overview
Restore the Default Portfast Port
Configuring Spanning Tree Timers
Restore the Default Timer Values
Configuring the Pseudo Root ID
Display Spanning Tree Information for Active Ports
Display Detailed Spanning Tree Information
Display the Spanning Tree Port-Specification Configuration
Display a Summary of the Spanning Tree Information for the Configuration
Specify MST Forward Time, Hello Time, and Max Age
Set the Spanning Tree Operating Mode
Specify MST Mode Configurations
Configuring the Spanning Tree Switch Priority
Configure the Spanning Tree Switch Priority
Restore the Default Spanning Tree Priority
Configure MST Properties of an Interface
Restore the Default MSTP Priority
Configuring the Interval Between Generation of Configuration Messages
Configure the MST Interval Between Generation of Configuration Messages
Restore the Default Interval Between Generation of Configuration Messages
Configuring the Maximum Hop Count
Configure the Maximum Hop Count
Restore the Default Maximum Hop Count
Configuring the Pseudo Root ID
Configuring Features Common to RSTP and MSTP
Clear Spanning Tree MSTP Counters
Configuring the Transit Hold Count
Configure the Transmit Hold Count
Restore the Default Transmit Hold Count Value
Configuring the Dynamic Path Cost
Dynamic Path Cost Topology Example
Configure the Dynamic Path Cost
Disable the Dynamic Path Cost Calculation
Configure the Dynamic Path Cost Lag Speed in an Aggregate Port
Disable the Dynamic Path Cost Lag Speed Calculation
Enable Spanning Tree Loop Guard
Show Spanning Tree Performance Data
Configuring Automatic Detection of Edge Devices or Bridges
Configure Automatic Detection of Edge Devices or Bridges
Disable Automatic Detection of Edge Devices or Bridges
Configuring the Restricted Role
Configuring the Topology Change
Restart the Protocol Migration Process
Configuring the Spanning Tree BPDU Receive Status
Configure the Spanning Tree BPDU Receive Status
Disable the Spanning Tree BPDU Receive Status
Configuring the Spanning Tree BPDU Transmit Status
Configure the Spanning Tree BPDU Transmit Status
Disable the Spanning Tree BPDU Transmit Status
Configuring the Spanning Tree L2GP Status
Configure the Spanning Tree L2GP Status
Display the Spanning Port Information
Display the MST Configuration and Status
Topology After Configuring the Bridge Priority and Port Path Cost in RSTP
The path cost of a port channel is the path cost corresponding to the aggregated speed of all the member ports of the port channel. The path cost of a port channel is determined when there is an operational status change for the port channel. There is no port channel path cost recalculation for operational status changes on individual member ports.
See Dynamic Path Cost Topology Example for the topology for this procedure. P1 and P2 are aggregated into a port channel interface.
SEFOS# show spanning-tree Root Id Priority 32768 Address 00:01:02:03:04:01 Cost 200000 Port 1 [Ex0/1] Max age 20 Sec, forward delay 15 Sec Hello Time is 2 Sec MST00 Spanning tree Protocol Enabled. MST00 is executing the mstp compatible Multiple Spanning Tree Protocol Bridge Id Priority 32768 Address 00:02:02:03:04:01 Max age is 20 sec, forward delay is 15 sec Hello Time is 2 sec Dynamic Path Cost is Disabled Dynamic Path Cost Lag-Speed Change is Disabled Name Role State Cost Prio Type ---- ---- ----- ---- ---- ------ Ex0/1 Root Forwarding 200000 128 SharedLan Ex0/2 Alternate Discarding 200000 128 SharedLan
SEFOS# configure terminal SEFOS(config)# spanning-tree pathcost dynamic
SEFOS(config)# set port-channel enable SEFOS(config)# interface port-channel 1 SEFOS(config-if)# no shutdown SEFOS(config-if)# exit SEFOS(config)# interface extreme-ethernet 0/1 SEFOS(config-if)# channel-group 1 mode active SEFOS(config-if)# exit SEFOS(config)# interface extreme-ethernet 0/2 SEFOS(config-if)# channel-group 1 mode active SEFOS(config-if)# exit
SEFOS# show spanning-tree Root Id Priority 32768 Address 00:01:02:03:04:01 Cost 99900 Port 25 [po1] Max age 20 Sec, forward delay 15 Sec Hello Time is 2 Sec MST00 Spanning tree Protocol Enabled. MST00 is executing the mstp compatible Multiple Spanning Tree Protocol Bridge Id Priority 32768 Address 00:02:02:03:04:01 Max age is 20 sec, forward delay is 15 sec Hello Time is 2 sec Dynamic Path Cost is Disabled Dynamic Path Cost Lag-Speed Change is Disabled Name Role State Cost Prio Type ---- ---- ----- ---- ---- ------ po1 Root Forwarding 99900 128 P2P
SEFOS# show spanning-tree Root Id Priority 32768 Address 00:01:02:03:04:01 Cost 0 Port 0 [0] This bridge is the root Max age 20 Sec, forward delay 15 Sec Hello Time is 2 Sec MST00 Spanning tree Protocol Enabled. MST00 is executing the mstp compatible Multiple Spanning Tree Protocol Bridge Id Priority 32768 Address 00:01:02:03:04:01 Max age is 20 sec, forward delay is 15 sec Hello Time is 2 sec Dynamic Path Cost is Disabled Dynamic Path Cost Lag-Speed Change is Disabled Name Role State Cost Prio Type ---- ---- ----- ---- ---- ------ po1 Designated Forwarding 99900 128 P2P
Note - Even after the cable is removed, the path cost is not changed. The path cost will be recalculated only when there is an operational status change of the port channel interface, and not when the operational status of a port in a bundle changes.
SEFOS(config)# interface port-channel 1 SEFOS(config-if)# shutdown SEFOS(config-if)# no shutdown SEFOS(config-if)# end SEFOS# show spanning-tree Root Id Priority 32768 Address 00:02:02:03:04:01 Cost 1900 Port 73 [po1] Max age 20 Sec, forward delay 15 Sec Hello Time 2 SecMST00Spanning tree Protocol has been enabledMST00 is executing the mstp compatible Multiple Spanning Tree ProtocolBridge Id Priority 32768 Address 00:01:02:03:04:01 Max age is 20 sec, forward delay is 15 sec Hello Time is 2 sec Dynamic Path Cost is Disabled Dynamic Path Cost Lag-Speed Change is EnabledName Role State Cost Prio Type---- ---- ----- ---- ---- ------po1 Root Forwarding 1900 128 P2P