CLI Reference Guide

Spanning Tree Commands 747
spanning-tree cost
Use the spanning-tree cost command in Interface Configuration mode to
configure the externally advertised spanning-tree path cost for a port. To
return to the default port path cost, use the no form of this command.
The path cost is used in the selection of an interface for the forwarding or
blocking states. Use the no form of the command to automatically select the
path cost based upon the speed of the interface.
Syntax
spanning-tree [vlan vlan-list ] cost cost
no spanning-tree cost
• cost — The port path cost. (Range: 1–200,000,000)
Default Configuration
The default value is to select the path cost based on the link speed.
• 40G Port path cost — 1400
•
10G Port path cost — 2000
•
1000 mbps (giga) — 20,000
•
100 mbps — 200,000
•
10 mbps — 2,000,000
• Port Channel—200,000,000 divided by the sum of the unidirectional link
speed (in Mbps) of each active member multiplied by 10 per section 13.6.1
of IEEE 802.1s.
Command Mode
Interface Configuration (gigabitethernet, port-channel, tengigabitethernet,
fortygigabitethernet) mode
User Guidelines
If the VLAN parameter is given, the path cost is configured only for the
selected VLANs (applies only when pvst or rapid-pvst mode is selected).
Configuration without the VLAN parameter configures the interface path
cost for RSTP, RSTP-PV, and STP-PV.
2CSNXXX_SWUM200.book Page 747 Tuesday, December 10, 2013 1:22 PM