3Com 4210 PWR Configuration Manual page 173

Configuring Port Priority
<4210> system-view
[4210] interface Ethernet1/0/1
[4210-Ethernet1/0/1] stp instance 1 cost 2000
Configuration example (B)
# Configure the path cost of Ethernet 1/0/1 in spanning tree instance 1 to be
calculated by the MSTP-enabled switch according to the IEEE 802.1D-1998
standard.
1 Perform this configuration in system view
<4210> system-view
[4210] undo stp interface Ethernet1/0/1 instance 1 cost
[4210] stp pathcost-standard dot1d-1998
2 Perform this configuration in Ethernet port view
<4210> system-view
[4210] interface Ethernet1/0/1
[4210-Ethernet1/0/1] undo stp instance 1 cost
[4210-Ethernet1/0/1] quit
[4210] stp pathcost-standard dot1d-1998
Port priority is an important criterion on determining the root port. In the same
condition, the port with the smallest port priority value becomes the root port.
A port on an MSTP-enabled switch can have different port priorities and play
different roles in different spanning tree instances. This enables packets of
different VLANs to be forwarded along different physical paths, so that
VLAN-based load balancing can be implemented.
You can configure port priority in one of the following two ways.
Configure port priority in system view
Table 126 Configure port priority in system view
Operation
Enter system view
Configure port priority for
specified ports
Configure port priority in Ethernet port view
Table 127 Configure port priority in Ethernet port view
Operation
Enter system view
Enter Ethernet port view
Configure port priority for the
port
Changing port priority of a port may change the role of the port and put the port
into state transition.
Command
system-view
stp interface interface-list
instance instance-id port
priority priority
Command
system-view
interface interface-type
interface-number
stp [ instance instance-id ]
port priority priority
Configuring Leaf Nodes 171
Description
-
Required
The default port priority is
128.
Description
-
-
Required.
The default port priority is
128.