American Fibertek SM8P-SFP - Manual (Page 185)

175 Rev.A1
18-May-11
Default: Auto
M Check:
Migration Check. It forces the port sending out an RSTP BPDU instead
of a legacy STP BPDU at the next transmission. The only benefit of this
operation is to make the port quickly get back to act as an RSTP port.
Click <M Check> button to send a RSTP BPDU from the port you
specified.