Before you begin • An MST must be specified and enabled on the device. • You must also know the specified MST instance ID and the interface used. Procedure (Optional) Designating the Neighbor Type A topology could contain both prestandard and IEEE 802.1s standard compliant devices. By default, ports can automatically detect prestandard devices, but they can still receive both standard and prestandard BPDUs. When there is a mismatch between a device and its neighbor, only the CIST runs on the interface. You can choose to set a port to send only prestandard BPDUs. The prestandard flag appears in all the show commands, even if the port is in STP compatibility mode.
To designate the neighbor type, perform this procedure: Before you begin An MST must be specified and enabled on the device. Configuring Multiple Spanning-Tree Protocol (Optional) Designating the Neighbor Type Command or Action Purpose Step 1 enable Example: Device> enable Enables privileged EXEC mode. Enter your password if prompted. Step 2 configure terminal Example: Device# configure terminal Enters global configuration mode. Step 3 interface interface-id Example: Device(config)# interface gigabitethernet 1/0/1 Specifies an interface to configure, and enters interface configuration mode. Valid interfaces include physical ports, VLANs, and port-channel logical interfaces.
The VLAN ID range is 1 to 4094. The port-channel range is 1 to 48. Step 4 spanning-tree link-type point-to-point Example: Device(config-if)# spanning-tree link-type point-to-point Specifies that the link type of a port is point-to-point. Step 5 end Example: Device(config-if)# end Returns to privileged EXEC mode. Configuring Multiple Spanning-Tree Protocol 26