spanning-tree mst pre-standard
spanning-tree mst pre-standard
Use the spanning-tree mst pre-standard interface configuration command to configure a port to send
only prestandard bridge protocol data units (BPDUs).
Syntax Description
This command has no arguments or keywords.
Command Default
The default state is automatic detection of prestandard neighbors.
Command Modes
Interface configuration
Command History
Release
12.2(44)EX
Usage Guidelines
The port can accept both prestandard and standard BPDUs. If the neighbor types are mismatched, only
the common and internal spanning tree (CIST) runs on this interface.
If a switch port is connected to a switch running prestandard Cisco IOS software, you must use the
Note
spanning-tree mst pre-standard interface configuration command on the port. If you do not configure
the port to send only prestandard BPDUs, the Multiple STP (MSTP) performance might diminish.
When the port is configured to automatically detect prestandard neighbors, the prestandard flag always
appears in the show spanning-tree mst commands.
Examples
This example shows how to configure a port to send only prestandard BPDUs:
Switch(config-if)# spanning-tree mst pre-standard
You can verify your settings by entering the show spanning-tree mst privileged EXEC command.
Related Commands
Command
show spanning-tree
Cisco IE 3000 Switch Command Reference
2-530
spanning-tree mst pre-standard
no spanning-tree mst pre-standard
Modification
This command was introduced.
mst instance-id
Chapter 2 IE 3000 Switch Cisco IOS Commands
Description
Displays multiple spanning-tree (MST) information,
including the prestandard flag, for the specified interface.
OL-13019-01