Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 256)

Changing STP bridge and port parameters
Table 44 on page 253 and Table 45 on page 254 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, Brocade recommends that you stay within the following
ranges, from section 8.10.2 of the IEEE STP specification. 2 * (forward_delay -1) >=
max_agemax_age >= 2 * (hello_time +1)
To change a STP bridge priority on a Brocade device to the highest value to make the device the root
bridge, enter the following command.
device(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.
device(config)#vlan 20
device(config-vlan-20)#spanning-tree priority 0
To make this change in the default VLAN, enter the following commands.
device(config)#vlan 1
device(config-vlan-1)#spanning-tree priority 0
Syntax: [no] spanning-tree [ forward-delay value] | [hello-time value] | [maximum-age value] |
[priority value]
The forward-delayvalue parameter specifies the forward delay and can be a value from 4 - 30
seconds. The default is 15 seconds.
NOTE
You can configure a Brocade device for faster convergence (including a shorter forward delay) using
Fast Span or Fast Uplink Span. Refer to
STP feature configuration on page 266.
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.
The priority value parameter specifies the priority and can be a value from 0 - 65535. A higher
numerical value means a lower priority. Thus, the highest priority is 0. The default is 32768.
You can specify some or all of these parameters on the same command line. If you specify more than
one parameter, you must specify them in the order shown above, from left to right.
Changing STP bridge and port parameters
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