Cisco IOS in a Nutshell, 2nd Edition

Name

spanning-tree vlan — global

Synopsis

spanning-tree vlan vlan-id [forward-time seconds | hello-time seconds |
max-age seconds | priority priority | protocol protocol | [root { primary
| secondary} [ diameter diameter [hello-time seconds]]]]
no spanning-tree vlan vlan-id

Configures

The port priority value for spanning-tree calculations

Default

Varies by option (details below)

Description

The command configures Spanning-Tree Protocol (STP) settings for each VLAN.

vlan-id

The ID of the VLAN, from 1 to 1,005.

forward-time

Optional. Sets the STP forward delay time, which can be from 4 to 30 seconds. Default is 15 seconds.

hello-time

Optional. Sets the interval between configuration messages from the root bridge; can be from 1 to 10 seconds. Default is 2 seconds.

max-age

Optional. Sets the maximum number of seconds that a BDPU packet is valid, which can be from 6 to 40 seconds. Default is 20 seconds.

priority

Optional. Sets the STP bridge priority, which can be from 0 to 65,535. Default is 128 (with the ieee protocol, default is 3,278).

protocol

Optional. Sets the STP protocol. Valid choices are dec, ibm, ieee, and vlan-bridge. ieee is the default.

root primary

Optional. Forces this device to be the root bridge.

root secondary

Optional. Forces this device to act as a secondary switch, which means it becomes the root switch if the primary root fails.

diameter

Optional. Set the maximum number of switches between any two end stations. Value can be from 2 to 7.

Example

! Enable spanning-tree on ...