Performing Mcheck Operation - 3Com 4210 PWR Configuration Manual

172 C 14: MSTP C
HAPTER
Specifying Whether the
Link Connected to a Port
Is a Point-to-point Link
Enabling MSTP
Performing mCheck
Operation
Configuration
Prerequisites
Configuration Procedure
ONFIGURATION
A smaller port priority value indicates a higher possibility for the port to become
the root port. If all the ports of a switch have the same port priority value, the port
priorities are determined by the port indexes. Changing the priority of a port will
cause spanning tree recalculation.
You can configure port priorities according to actual networking requirements.
Configuration example
# Configure the port priority of Ethernet1/0/1 in spanning tree instance 1 to be 16.
1 Perform this configuration in system view
<4210> system-view
[4210] stp interface Ethernet1/0/1 instance 1 port priority 16
2 Perform this configuration in Ethernet port view
<4210> system-view
[4210] interface Ethernet1/0/1
[4210-Ethernet1/0/1] stp instance 1 port priority 16
Refer to "Specifying Whether the Link Connected to a Port Is Point-to-point Link"
on page 165.
Refer to "Enabling MSTP" on page 166.
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 turns
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-compatible mode. It
remains in the STP-compatible mode. In this case, you can force the port to transit
to the MSTP-compatible mode by performing the mCheck operation on the port.
MSTP runs normally on the switch.
You can perform the mCheck operation in the following two ways.