Cisco WS-C3560E-48PD-SF Command Reference - Page 623

Chapter 2 Catalyst 3560 Switch Cisco IOS Commands 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). spanning-tree mst pre-standard no spanning-tree mst pre-standard 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(25)SEC Modification This command was introduced. 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. Note If a switch port is connected to a switch running prestandard Cisco IOS software, you must use the 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 mst instance-id Description Displays multiple spanning-tree (MST) information, including the prestandard flag, for the specified interface. 78-16405-05 Catalyst 3560 Switch Command Reference 2-591