Chapter 19
| Spanning Tree Commands
– 528 –
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. When the short path cost
method is selected and the default path cost recommended by the IEEE 8021w
standard exceeds 65,535, the default is set to 65,535.
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 path cost method (page 519) is set to short, the maximum value for
path cost is 65,535.
Example
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree cost 50
Console(config-if)#
11. Use the spanning-tree pathcost method command to set the path cost method.
Gigabit Ethernet 3-10 2,000-200,000
10G Ethernet 1-5 200-20,000
Table 97: Default STA Path Costs
Port Type Short Path Cost
(IEEE 802.1D-1998)
Long Path Cost
(IEEE 802.1D-2004)
Ethernet 65,535 1,000,000
Fast Ethernet 65,535 100,000
Gigabit Ethernet 10,000 10,000
10G Ethernet 1,000 1,000
Table 96: Recommended STA Path Cost Range (Continued)
Port Type Short Path Cost
(IEEE 802.1D-1998)
Long Path Cost
(IEEE 802.1D-2004)
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