Administrator Guide

Layer 2 Switching Commands 761
Syntax
spanning-tree [vlan vlan-list] cost cost
no spanning-tree cost
• cost — The port path cost.
Default Configuration
The default cost value (0) causes the switch 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 802.1 s.
Command Mode
Interface Configuration (gigabitethernet, port-channel, tengigabitethernet,
fortygigabitethernet) mode
User Guidelines
Dell EMC Networking spanning tree uses long values for spanning tree costs.
The range for path cost for a port is 0-200,000,000. The range for path cost for
a VLAN is 1-200,000,000. Use the no form of the command to calculate the
cost based on the interface speed. A zero path cost causes the switch to
calculate the path cost based upon the speed of the interface.
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 STP, RSTP, and the MSTP common instance.