Foundry Networks FESX - Changing Stp Bridge and Port Parameters

Configuring Spanning Tree Protocol (STP) and IronSpan Features
December 2005 © Foundry Networks, Inc. 7 - 5
Enabling or Disabling STP on an Individual Port
Use the following procedure to disable or enable STP on an individual port.
NOTE: If you change the STP state of the primary port in a trunk group, the change affects all ports in the trunk
group.
To enable STP on an individual port, enter commands such as the following:
FastIron SuperX Router(config)# interface 1/1
FastIron SuperX Router(config-if-e1000-1/1)# spanning-tree
Syntax: [no] spanning-tree
Changing STP Bridge and Port Parameters
Table 7.3 on page 7-3 and Table 7.4 on page 7-3 list the default STP parameters. If you need to change the
default value for an STP parameter, use the following procedures.
Changing STP Bridge Parameters
NOTE: If you plan to change STP bridge timers, Foundry recommends that you stay within the following ranges,
from section 8.10.2 of the IEEE STP specification.
2 * (forward_delay -1) >= max_age
max_age >= 2 * (hello_time +1 )
To change a Foundry device’s STP bridge priority to the highest value to make the device the root bridge, enter the
following command:
FESX424 Router(config)# spanning-tree priority 0
The command in this example changes the priority on a device on which you have not configured port-based
VLANs. The change applies to the default VLAN. If you have configured a port-based VLAN on the device, you
can configure the parameters only at the configuration level for individual VLANs. Enter commands such as the
following:
FESX424 Router(config)# vlan 20
FESX424 Router(config-vlan-20)# spanning-tree priority 0
To make this change in the default VLAN, enter the following commands:
FESX424 Router(config)# vlan 1
FESX424 Router(config-vlan-1)# spanning-tree priority 0
Syntax: [no] spanning-tree [forward-delay <value>] | [hello-time <value>] | [maximum-age <value>] | [priority
<value>]
The forward-delay <value> parameter specifies the forward delay and can be a value from 4 – 30 seconds. The
default is 15 seconds.
NOTE: You can configure a Foundry device for faster convergence (including a shorter forward delay) using Fast
Span. See “Configuring IronSpan Features” on page 7-16.
The hello-time <value> parameter specifies the hello time and can be a value from 1 – 10 seconds. The default
is 2 seconds.
NOTE: This parameter applies only when this device or VLAN is the root bridge for its spanning tree.
The maximum-age <value> parameter specifies the amount of time the device waits for receipt of a configuration
BPDU from the root bridge before initiating a topology change. You can specify from 6 – 40 seconds. The default
is 20 seconds.