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Configuring path costs of ports, Configuration example, Configuring the port priority – H3C Technologies H3C S5560 Series Switches User Manual

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Configuring path costs of ports

When the path cost of a port changes, the system recalculates the role of the port and initiates a state

transition.
To configure the path cost of a port:

Step Command Remarks

1.

Enter system view.

system-view

N/A

2.

Enter Layer 2 Ethernet or

aggregate interface view.

interface interface-type interface-number

N/A

3.

Configure the path cost of the
ports.

In STP/RSTP mode:
stp cost cost

In PVST mode:

stp vlan vlan-id-list cost cost

In MSTP mode:

stp [ instance instance-list ] cost cost

By default, the system
automatically calculates the

path cost of each port.

Configuration example

# In MSTP mode, perform the following tasks:

Configure the device to calculate the default path costs of its ports by using IEEE 802.1d-1998.

Set the path cost of GigabitEthernet 1/0/3 to 200 on MSTI 2.

system-view

[Sysname] stp pathcost-standard dot1d-1998

Cost of every port will be reset and automatically re-calculated after you change the

current pathcost standard. Continue?[Y/N]:y

Cost of every port has been re-calculated.

[Sysname] interface gigabitethernet 1/0/3

[Sysname-GigabitEthernet1/0/3] stp instance 2 cost 200

# In PVST mode, perform the following tasks:

Configure the device to calculate the default path costs of its ports by using IEEE 802.1d-1998.

Set the path cost of GigabitEthernet 1/0/3 to 2000 on VLAN 20 through VLAN 30.

system-view

[Sysname] stp pathcost-standard dot1d-1998

Cost of every port will be reset and automatically re-calculated after you change the

current pathcost standard. Continue?[Y/N]:y

Cost of every port has been re-calculated

[Sysname] interface gigabitethernet 1/0/3

[Sysname-GigabitEthernet1/0/3] stp vlan 20 to 30 cost 2000

Configuring the port priority

The priority of a port is a factor that determines 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 is elected as the root port.