4000 Router Series Layer 2 - LAN Switching Configuration Guide

To enable the spanning tree feature:

Step Command Remarks

1. Enter system view.

system-view N/A

2. Enable the spanning tree

feature.

stp global enable

By default, the spanning tree

feature is disabled globally.

3. Enter Layer 2 Ethernet

interface view.

interface interface-type

interface-number

N/A

4. (Optional.) Enable the

spanning tree feature for the

port.

stp enable

By default, the spanning tree

feature is enabled on all ports.

Performing mCheck

The mCheck feature enables user intervention in the port status transition process.

If a port on a device that is running MSTP or RSTP connects to an STP device, this port automatically

transits to STP mode when the port receives STP BPDUs. However, if the peer STP device is shut down or

removed and the local device cannot detect the change, the local device cannot automatically transit

back to the original mode. To forcibly transit the port to operate in the original mode, you can perform

an mCheck operation.

Suppose a scenario where Device A, Device B, and Device C are connected in sequence. Device A runs

STP, Device B does not run any spanning tree protocol, and Device C runs RSTP or MSTP. In this case,

when Device C receives an STP BPDU transparently transmitted by Device B, the receiving port transits to

the STP mode. If you configure Device B to run RSTP or MSTP with Device C, you must perform mCheck

operations on the ports interconnecting Device B and Device C.

The following methods for performing mCheck produce the same result.

Performing mCheck globally

Step Command

1. Enter system view.

system-view

2. Perform mCheck.

stp global mcheck

Performing mCheck in interface view

Step Command

1. Enter system view.

system-view

2. Enter Layer 2 Ethernet interface view.

interface interface-type interface-number

3. Perform mCheck.

stp mcheck