3Com 5500-SI - Configuring a Port to Connect to Point-To-Point Link; Enabling MSTP; Mcheck Configuration; Prerequisites

184 CHAPTER 13: MSTP CONFIGURATION
Configuring the priority of a port in Ethernet port view
Changes of port priorities can cause MSTP to redetermine the roles of ports, resulting
in state transition of ports.
A lower port priority value indicates a higher port priority. If all ports of a switch have
the same port priority setting, the actual port priorities are determined by the port
indexes.
You can configure port priorities based on the specific networking requirements.
Configuration example
Configure the priority of port Ethernet1/0/1 in spanning tree instance 1 to be 16.
1 Configure in system view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] stp interface ethernet1/0/1 instance 1 port priority 16
2 Configure in Ethernet port view.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] interface ethernet1/0/1
[S5500-Ethernet1/0/1] stp instance 1 port priority 16
Configuring a Port to
Connect to
Point-to-Point Link
Refer to “Configuring a Port to Connect to Point-to-Point Link”.
Enabling MSTP Refer to “Enabling MSTP”.
mCheck Configuration As mentioned previously, ports on an MSTP-enabled switch can operate in three
modes: STP mode, RSTP mode, and MSTP mode. On a switched network, if a port on
a switch running MSTP is connected to a switch running STP or RSTP, it automatically
transits to STP or RSTP mode. But when the switch running STP or RSTP is
disconnected, the port cannot transit back to MSTP mode automatically; it remains in
STP or RSTP mode.
In this case, you can force the port to operate in MSTP mode by performing the
mCheck operation.
Prerequisites Configure MSTP on the switch properly.
Table 165 Configure the priority of a port in Ethernet port view
Operation Command Description
Enter system view system-view -
Enter Ethernet port view interface interface-type
interface-number
-
Configure the port priority of
the port
stp [ instance instance-id ]
port priority priority
Required.
By default, all Ethernet ports of a
switch have the same priority,
namely 128.