Reference Guide

The range is from 1 to 10.
The default is 2 seconds.
• Change the max-age parameter.
PROTOCOL SPANNING TREE RSTP mode
max-age seconds
The range is from 6 to 40.
The default is 20 seconds.
To view the current values for global parameters, use the show spanning-tree rstp command from
EXEC privilege mode.
Modifying Interface Parameters
On interfaces in Layer 2 mode, you can set the port cost and port priority values.
• Port cost — a value that is based on the interface type. The previous table lists the default values. The
greater the port cost, the less likely the port is selected to be a forwarding port.
• Port priority — influences the likelihood that a port is selected to be a forwarding port in case that
several ports have the same port cost.
To change the port cost or priority of an interface, use the following commands.
• Change the port cost of an interface.
INTERFACE mode
spanning-tree rstp cost cost
The range is from 0 to 65535.
The default is listed in the previous table.
• Change the port priority of an interface.
INTERFACE mode
spanning-tree rstp priority priority-value
The range is from 0 to 15.
The default is 128.
To view the current values for interface parameters, use the show spanning-tree rstp command
from EXEC privilege mode.
Configuring an EdgePort
The EdgePort feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner.
In this mode an interface forwards frames by default until it receives a BPDU that indicates that it should
behave otherwise; it does not go through the Learning and Listening states. The bpduguard shutdown-
on-violation option causes the interface hardware to shut down when it receives a BPDU. When only
bpduguard is implemented, although the interface is placed in an Error Disabled state when receiving
the BPDU, the physical interface remains up and spanning-tree drops packets in the hardware after a
820
Rapid Spanning Tree Protocol (RSTP)