•
Be careful when switching between spanning tree modes. Changing modes
stops all spanning-tree instances for the previous mode and restarts the system
in the new mode, temporarily disrupting user traffic.
Example
The following example configures the switch to use Rapid Spanning Tree:
SSE-G2252(config)#spanning-tree mode rstp
SSE-G2252(config)#
spanning-tree pathcost method
This command configures the path cost method used for Rapid Spanning Tree and
Multiple Spanning Tree. Use the no form to restore the default.
Syntax
spanning-tree pathcost method {long | short}
no spanning-tree pathcost method
long - Specifies 32-bit based values that range from 1-200,000,000. This method is
based on the IEEE 802.1w Rapid Spanning Tree Protocol.
short - Specifies 16-bit based values that range from 1-65535. This method is
based on the IEEE 802.1 Spanning Tree Protocol.
Default Setting
Long method
Command Mode
Global Configuration
Command Usage
•
The path cost method is used 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. Note that path cost
("spanning-tree cost" on page
("spanning-tree port-priority" on page
•
The path cost methods apply to all spanning tree modes (STP, RSTP and MSTP).
Specifically, the long method can be applied to STP since this mode is supported by
a backward compatible mode of RSTP.
Example
SSE-G2252(config)#spanning-tree pathcost method long
SSE-G2252(config)#
Chapter 34: Spanning Tree Commands
34-18) takes precedence over port priority
34-26).
34-7