Spanning-Tree Operation

802.1D Spanning-Tree Protocol (STP)

Enabling STP implements the spanning tree protocol for all physical ports on the switch, regardless of whether multiple VLANs are configured. Disabling STP removes protection against redundant loops that can significantly slow or halt a network.

This command enables STP with the current parameter settings or disables STP without losing the most-recently configured parameter settings. (To learn how the switch handles parameter changes, how to test changes without losing the previous settings, and how to replace previous settings with new settings, refer to the chapter titled “Switch Memory and Configuration” in the Management and Configuration Guide for your switch.) When enabling STP, you can also include the STP general and per-port parameters described in the next two sections. When you use the “no” form of the command, you can do so only to disable STP. (STP parameter settings are not changed when you disable STP.)

C a u t i o n

Because incorrect STP settings can adversely affect network performance,

 

ProCurve recommends that you use the default STP parameter settings. You

 

should not change these settings unless you have a strong understanding of

 

how STP operates. For more on STP, see the IEEE 802.1D standard.

 

Reconfiguring General STP Operation on the Switch. You can config­

 

 

ure one or more of the following parameters:

 

Table 5-3. General STP Operating Parameters

 

 

 

 

 

 

 

 

Name

Default

Range

Function

 

 

 

 

 

 

 

 

priority

32768

0 - 65535

Specifies the priority value used along with the

 

 

 

 

 

switch MAC address to determine which device is

 

 

 

 

 

root. The lower a priority value, the higher the

 

 

 

 

 

priority.

 

 

*maximum-age

20 seconds

6 - 40

Maximum received message age the switch

 

 

 

 

seconds

allows for STP information before discarding the

 

 

 

 

 

message.

 

 

*hello-time

2 seconds

1 - 10

Time between messages transmitted when the

 

 

 

 

 

switch is the root.

 

 

*forward-delay

15 seconds

4 - 30

Time the switch waits before transitioning from the

 

 

 

 

seconds

listening to the learning state, and between the

 

 

 

 

 

learning state to the forwarding state.

*The switch uses its own maximum-age, hello-time, and forward-delay settings only if it is operating as the root device. If another device is operating as the root device, then the switch uses the other device’s settings for these parameters.

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