Configuring Spanning-Tree Timers On The Switch - Cisco WS-C6506 Software Manual

Chapter 7 Configuring Spanning Tree
This example shows how to display spanning-tree BPDU statistics:
Console> show spantree statistics bpdu
Total
Rate(/sec)
This example shows how to clear spanning-tree BPDU statistics:
Console> (enable) clear spantree statistics bpdu
Spanning tree BPDU statistics cleared on the switch.
Console> (enable)

Configuring Spanning-Tree Timers on the Switch

The spanning-tree timers affect the spanning-tree performance. You can configure the spanning-tree
timers for a VLAN in PVST+ or an MISTP instance in MISTP mode. If you do not specify a VLAN
when the switch is in PVST+ mode, VLAN 1 is assumed, or if you do not specify an MISTP instance
when the switch is in MISTP mode, MISTP instance 1 is assumed.
These sections describe how to configure the spanning-tree timers:
•
•
•
Be careful when using these commands. For most situations, we recommend that you use the set
Caution
spantree root and set spantree root secondary commands to modify the spanning tree performance
parameters.
Table 7-7
Table 7-7
Variable
Hello Time
Maximum Age
Timer
Forward Delay
Timer
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Configuring the Hello Time, page 7-50
Configuring the Forward Delay Time, page 7-50
Configuring the Maximum Aging Time, page 7-51
describes the switch variables that affect spanning tree performance.
Spanning-Tree Timers
Description
Determines how often the switch broadcasts its hello message to
other switches.
Measures the age of the received protocol information that is
recorded for a port and ensures that this information is discarded
when its age limit exceeds the value of the maximum age parameter
that is recorded by the switch. The timeout value is the maximum
age parameter of the switches.
Monitors the time that is spent by a port in the learning and
listening states. The timeout value is the forward delay parameter
of the switches.
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Configuring Spanning-Tree Timers on the Switch
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Default
2 seconds
20 seconds
15 seconds
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