Step
1.
Enter system view.
2.
Specify a standard for the
device to use when it
calculates the default path
costs of its ports.
Configuring path costs of ports
When the path cost of a port changes, the system re-calculates the role of the port and initiates a state
transition.
To configure the path cost of ports:
Step
1.
Enter system view.
2.
Enter interface view or port
group view.
3.
Configure the path cost of the
ports.
Configuration example
# In MSTP mode, specify the device to use IEEE 802.1d- 1 998 to calculate the default path costs of its ports,
and set the path cost of GigabitEthernet 4/0/1 to 200 on MSTI 2.
<Sysname> system-view
[Sysname] stp pathcost-standard dot1d-1998
[Sysname] interface GigabitEthernet 4/0/1
[Sysname-GigabitEthernet4/0/1] stp instance 2 cost 200
Configuring the port priority
The priority of a port is an important factor in determining whether the port can be elected as the root
port of a device. If all other conditions are the same, the port with the highest priority will be elected as
the root port.
On a spanning tree device, a port can have different priorities and play different roles in different
spanning trees, so that data from different VLANs can be propagated along different physical paths to
implement per-VLAN load balancing. You can set port priority values based on your actual network
requirements.
If the port priority changes, the system re-calculates the port role and initiates a state transition.
Command
system-view
stp pathcost-standard
{ dot1d-1998 | dot1t | legacy }
Command
system-view
•
Enter Ethernet interface view or Layer 2
aggregate interface view:
interface interface-type
interface-number
•
Enter port group view:
port-group manual port-group-name
•
In STP/RSTP mode:
stp cost cost
•
In MSTP mode:
stp [ instance instance-id ] cost cost
65
Remarks
N/A
Optional.
The default standard used by the
device is legacy.
Remarks
N/A
Use one of the commands.
Use one of the commands.
By default, the system
automatically calculates the
path cost of each port.