User manual

S PANNING T REE C OMMANDS
4-225
spanning-tree mst cost
This command configures the path cost on a spanning instance in the
Multiple Spanning Tree. Use the no form to restore the default.
Syntax
spanning-tree mst instance_id cost cost
no spanning-tree mst instance_id cost
• instance_id - Instance identifier of the spanning tree.
(Range: 1-4094, no leading zeroes)
• cost - Path cost for an interface. (Range: 1-200,000,000)
The recommended range is -
- Ethernet: 200,000-20,000,000
- Fast Ethernet: 20,000-2,000,000
- Gigabit Ethernet: 2,000-200,000
Default Setting
• Ethernet – half duplex: 2,000,000; full duplex: 1,000,000; trunk:
500,000
• Fast Ethernet – half duplex: 200,000; full duplex: 100,000; trunk:
50,000
• Gigabit Ethernet – full duplex: 10,000; trunk: 5,000
Command Mode
Interface Configuration (Ethernet, Port Channel)
Command Usage
• Each spanning-tree instance is associated with a unique set of VLAN
IDs.
• This command is used by the multiple spanning-tree algorithm to
determine the best path between devices. Therefore, lower values
should be assigned to interfaces attached to faster media, and higher
values assigned to interfaces with slower media.
• Path cost takes precedence over interface priority.