spanning-tree cost
This command configures the spanning tree path cost for th e specifi ed interface .
Use the
no
form to restore the default auto-configuration mode.
Syntax
spanning-tree
cost
cost
no spanning-tree cost
cost - The path cost for the port.
(Range: 0 for auto-configuration, 1-65535 for short path cost method28,
1-200,000,000 for long path cost method)
Table 33-2 Recommended STA Path Cost Range
Port Type Short Path Cost Long Path Cost
(IEEE 802.1D-1998) (802.1D-2004)
Gigabit Ethernet 2,000-65,535 2,000-200,000
10G Ethernet 200-20,000 200-20,000
Default Setting
By default, the system automaticall y detects the spee d and duple x mode used
on each port, and configures the path cost according to the values shown
below. Path cost “0” is used to indicate auto-co nfiguration mo de. When the
short path cost method is selected and the default path cost recomm ended by
the IEEE 8021D-2004 standard exceeds 65,535, the default is set to 65,535.
Table 33-3 Default STA Pa th Co sts
Port Type Short Path Cost Long Path Cost
(IEEE 802.1D-1998) (802.1D-2004)
Gigabit Ethernet 10,000 10,000
10G Ethernet 1,000 1,000
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• This command is used by the S panning Tree Algorithm to determine the best
path between devices. Therefore, lower values should be assigne d to ports
attached to faster media, and higher values assigned t o ports wi th slower
media.
• Path cost takes precedence over port priority.
• When the spanning-tree pat hcost metho d (page 33-6) i s s et to shor t, the
maximum value for path cost is 65,535.
28. Use the spanning-tree pathcost method command on page 33-6 to set the path cost method.
33-12
Spanning Tree Commands
33