Switch Configuration Guide

Spanning Tree Configuration Command Set
Configuring Spanning Tree Loop Protect Features
6-120 Matrix NSA Series Configuration Guide
set spantree disputedbpduthreshold (Section 6.2.3.18)
show spantree disputedbpduthreshold (Section 6.2.3.19)
clear spantree disputedbpduthreshold (Section 6.2.3.20)
show spantree nonforwardingreason (Section 6.2.3.21)