Users Guide

The following table displays the default values for RSTP.
Table 72. RSTP Default Values
RSTP Parameter Default Value
Forward Delay 15 seconds
Hello Time 2 seconds
Max Age 20 seconds
Port Cost:
• 1–Gigabit Ethernet interfaces
• 10–Gigabit Ethernet interfaces
• 40–Gigabit Ethernet interfaces
• Port Channel with 1-Gigabit Ethernet interfaces
• Port Channel with 10-Gigabit Ethernet interfaces
Port Cost:
• 20000
• 2000
• 2000
• 18000
• 1800
Port Priority 128
To change these parameters, use the following commands.
• Change the forward-delay parameter.
PROTOCOL SPANNING TREE RSTP mode
forward-delay seconds
The range is from 4 to 30.
The default is 15 seconds.
• Change the hello-time parameter.
PROTOCOL SPANNING TREE RSTP mode
hello-time seconds
NOTE: With large congurations (especially those congurations with more ports) Dell Networking recommends
increasing the hello-time.
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 — inuences the likelihood that a port is selected to be a forwarding port in case that several ports have the same
port cost.
Rapid Spanning Tree Protocol (RSTP)
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