Planet IGSW-2840 User Manual page 544

Fast Ethernet
Gigabit
Ethernet
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.
Port Type
Ethernet
Fast Ethernet
Gigabit Ethernet
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 4-206) 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)#
Half 19
DuplexFull 18
DuplexTrunk 15
Full 4
DuplexTrunk 3
Table 5-64 Recommended STA Path Cost
Link Type
Half Duplex
Full Duplex
Trunk
Half Duplex
Full Duplex
Trunk
Full Duplex
Trunk
Table 5-65 Default STA Path Costs
544
User's Manual of IGSW-2840
200,000
100,000
50,000
10,000
5,000
IEEE 802.1w-2001
2,000,000
1,000,000
500,000
200,000
100,000
50,000
10,000
5,000