3Com Switch 7750 Configuration Guide Guide

246 CHAPTER 29: MSTP CONFIGURATION
<SW7750> system-view
[SW7750] interface ethernet1/0/1
[SW7750-Ethernet1/0/1] stp instance 1 port priority 16
Point-to-point
Link-Related
Configuration
Refer to “Point-to-point Link-Related Configuration”.
MSTP Configuration Refer to “MSTP Configuration”.
The mCheck
Configuration
As mentioned previously, ports on an MSTP-enabled switch can operate in three
modes: STP-compatible, RSTP-compatible, and MSTP.
A port on an MSTP-enabled switch operating as an upstream switch transits to the
STP-compatible mode when it has an STP-enabled switch connected to it. When
the STP enabled downstream switch is then replaced by an MSTP-enabled switch,
the port cannot automatically transit to the MSTP mode. It remains in the
STP-compatible mode. In this case, you can force the port to transit to the MSTP
mode by performing the mCheck operation on the port.
Similarly, a port on an RSTP-enabled switch operating as an upstream switch
transits to the STP-compatible mode when it has an STP enabled switch connected
to it. When the STP enabled downstream switch is then replaced by an
MSTP-enabled switch, the port cannot automatically transit to the MSTP operation
mode. It remains in the STP-compatible mode. In this case, you can force the port
to transit to the MSTP mode by performing the mCheck operation on the port.
Prerequisites MSTP runs normally on the switch.
Configuration Procedure You can perform the mCheck operation in the following two ways.
Performing the mCheck operation in system view
Performing the mCheck operation in Ethernet port view
Configuration Example # Perform the mCheck operation on Ethernet1/0/1 port
Tabl e 179 Perform the mCheck operation in system view
Operation Command Description
Enter system view System-view -
Perform the mCheck
operation
stp [ interface interface-list ]
mcheck
Required
Tabl e 180 Perform the mCheck operation in Ethernet port view
Operation Command Description
Enter system view system-view -
Enter Ethernet port view
interface interface-type
interface-number
-
Perform the mCheck
operation
stp mcheck Required