Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 534)

Spanning Tree Commands
Software Reference for x310 Series Switches
19.44 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
spanning-tree guard root
Use this command in Interface Configuration mode for a switch port only to enable the
Root Guard feature for the switch port. The root guard feature disables reception of
superior BPDUs. You can use this command for RSTP, STP or MSTP.
Use the no variant of this command to disable the root guard feature for the port.
Syntax spanning-tree guard root
no spanning-tree guard root
Mode Interface Configuration mode for a switch port interface only.
Usage The Root Guard feature makes sure that the port on which it is enabled is a designated
port. If the Root Guard enabled port receives a superior BPDU, it goes to a Listening state
(for STP) or discarding state (for RSTP and MSTP).
Example
awplus# configure terminal
awplus(config)# interface port1.0.2
awplus(config-if)# spanning-tree guard root