1-21 
 
In auto mode, if a port frequently receives MSTP packets of different formats alternately, the port will be 
forcibly placed in the discarding state and no longer forwards MSTP packets. The physical state of the 
port will be displayed as STP DOWN. To restore such a port, you can first run the shutdown command 
and then the undo shutdown command on it. 
 
Configuration procedure 
Follow these steps to configure how a port recognizes and sends MSTP packets (in system view): 
To do...  Use the command...  Remarks 
Enter system view
 
system-view 
— 
Configure how a port 
recognizes and sends 
MSTP packets
 
stp interface 
interface-list
 
compliance { auto | dot1s | 
legacy } 
Required 
By default, a port recognizes and sends 
MSTP packets in the automatic mode. 
That is, it determines the format of 
packets to be sent according to the 
format 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...  Remarks 
Enter system view
 
system-view 
— 
Enter Ethernet port view
 
interface interface-type 
interface-number 
— 
Configure how a port 
recognizes and sends 
MSTP packets
 
stp compliance { auto | 
dot1s | legacy } 
Required 
By default, a port recognizes and sends 
MSTP packets in the automatic mode. 
That is, it determines the format of 
packets to be sent according to the 
format of the packets received.
 
 
Configuration example 
# Configure Ethernet 1/0/1 to recognize and send packets in dot1s format. 
<Sysname> 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 compliance 
Configuring the MSTP Operation Mode 
To make an MSTP-enabled switch compatible with STP/RSTP, MSTP provides the following three 
operation modes: