1-21In auto mode, if a port frequently receives MSTP packets of different formats alternately, the port will beforcibly placed in the discarding state and no longer forwards MSTP packets. The physical state of theport will be displayed as STP DOWN. To restore such a port, you can first run the shutdown commandand then the undo shutdown command on it.Configuration procedureFollow these steps to configure how a port recognizes and sends MSTP packets (in system view):To do... Use the command... RemarksEnter system view system-view —Configure how a portrecognizes and sendsMSTP packetsstp interface interface-listcompliance { auto | dot1s |legacy }RequiredBy default, a port recognizes and sendsMSTP packets in the automatic mode.That is, it determines the format ofpackets to be sent according to theformat of the packets received.Follow these steps to configure how a port recognizes and sends MSTP packets (in Ethernet port view):To do... Use the command... RemarksEnter system view system-view —Enter Ethernet port view interface interface-typeinterface-number —Configure how a portrecognizes and sendsMSTP packetsstp compliance { auto |dot1s | legacy }RequiredBy default, a port recognizes and sendsMSTP packets in the automatic mode.That is, it determines the format ofpackets to be sent according to theformat of the packets received.Configuration example# Configure Ethernet 1/0/1 to recognize and send packets in dot1s format. system-view[Sysname] interface Ethernet 1/0/1[Sysname-Ethernet1/0/1] stp compliance dot1s# Restore the default mode for Ethernet 1/0/1 to recognize/send MSTP packets.[Sysname-Ethernet1/0/1] undo stp complianceConfiguring the MSTP Operation ModeTo make an MSTP-enabled switch compatible with STP/RSTP, MSTP provides the following threeoperation modes:
