S
PANNING
T
REE
C
OMMANDS
4-207
Default Setting
By default, the system automatically detects the speed and duplex mode
used on each port, and configures the path cost according to the values
shown below. Path cost “0” is used to indicate auto-configuration
mode.
• Ethernet – half duplex: 2,000,000; full duplex: 1,000,000; trunk:
500,000
• Fast Ethernet – half duplex: 200,000; full duplex: 100,000; trunk:
50,000
• Gigabit Ethernet – full duplex: 10,000; trunk: 5,000
• 10 Gigabit Ethernet – full duplex: 1000; trunk: 500
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• This command is used by the Spanning Tree Algorithm to determine
the best path between devices. Therefore, lower values should be
assigned to ports attached to faster media, and higher values assigned
to ports with slower media.
• Path cost takes precedence over port priority.
• When the spanning-tree pathcost method (page -200) is set to short,
the maximum value for path cost is 65,535.
Example
spanning-tree port-priority
This command configures the priority for the specified interface. Use the
no form to restore the default.
Syntax
spanning-tree port-priority priority
no spanning-tree port-priority
priority - The priority for a port. (Range: 0-240, in steps of 16)
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree cost 50
Console(config-if)#