Installation manual

4-228
SIGNAMAX LLC • www.signamax.eu
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 spanning-tree pathcost method (page 4-222) is set to short, the
maximum value for path cost is 65,535.
Example
Table 4-62 Recommended STA Path Cost
Port Type Link Type IEEE 802.1D-1998 IEEE 802.1w-2001
Ethernet Half Duplex
Full Duplex
Trunk
100
95
90
2,000,000
1,999,999
1,000,000
Fast Ethernet Half Duplex
Full Duplex
Trunk
19
18
15
200,000
100,000
50,000
Gigabit Ethernet Full Duplex
Trunk
4
3
10,000
5,000
Table 4-63 Default STA Path Costs
Port Type Link Type IEEE 802.1w-2001
Ethernet Half Duplex
Full Duplex
Trunk
2,000,000
1,000,000
500,000
Fast Ethernet Half Duplex
Full Duplex
Trunk
200,000
100,000
50,000
Gigabit Ethernet Full Duplex
Trunk
10,000
5,000
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree cost 50
Console(config-if)#