Adjusting Spanning Tree Parameters

You may need to adjust certain Spanning Tree parameters if the default values are not suitable for your bridge configuration. Parameters affecting the entire Spanning Tree are configured with variations of the global bridge configuration commands. Interface-specific parameters are configured with variations of the Spanning Tree port configuration commands. Default settings are listed in Spanning Tree Port Default Settings:

Spanning Tree Port Default Settings

Setting	Default Value
Bridge priority mode	802.1t
Bridge priority	32768
Port priority	128
Port cost	0 (automatically calculated based on port speed)
Hello time (bridge and ports)	2 seconds
Bridge forward delay	15 seconds
Bridge maximum aging time	20 seconds

Use the commands in the following sections to adjust these defaults.

Note

Poorly chosen adjustments to these parameters can have a negative impact on network performance. Please refer to the IEEE 802.1D specification for guidance.