Users Guide
Adding and Removing Interfaces
To add and remove interfaces, use the following commands.
To add an interface to the Rapid Spanning Tree topology, congure it for Layer 2 and it is automatically added. If you previously disabled
RSTP on the interface using the command
no spanning-tree 0 command, re-enable it using the spanning-tree 0 command.
• Remove an interface from the Rapid Spanning Tree topology.
no spanning-tree 0
Modifying Global Parameters
You can modify RSTP parameters.
The root bridge sets the values for forward-delay, hello-time, and max-age and overwrites the values set on other bridges participating in
the Rapid Spanning Tree group.
• Forward-delay — the amount of time an interface waits in the Listening state and the Learning state before it transitions to the
Forwarding state.
• Hello-time — the time interval in which the bridge sends RSTP BPDUs.
• Max-age — the length of time the bridge maintains conguration information before it refreshes that information by recomputing the
RST topology.
NOTE: Dell Networking recommends that only experienced network administrators change the Rapid Spanning Tree group
parameters. Poorly planned modication of the RSTP parameters can negatively aect network performance.
The following table displays the default values for RSTP.
Table 75. RSTP Default Values
RSTP Parameter Default Value
Forward Delay 15 seconds
Hello Time 2 seconds
Max Age 20 seconds
Port Cost:
• 100-Mb/s Ethernet interfaces
• 1-Gigabit Ethernet interfaces
• 10-Gigabit Ethernet interfaces
• 25-Gigabit Ethernet interfaces
• 40-Gigabit Ethernet interfaces
• 50-Gigabit Ethernet interfaces
• 100-Gigabit Ethernet interfaces
• Port Channel with 100 Mb/s Ethernet interfaces
• Port Channel with 1-Gigabit Ethernet interfaces
• Port Channel with 10-Gigabit Ethernet interfaces
• Port Channel with 40-Gigabit Ethernet interfaces
• Port Channel with 25-Gigabit Ethernet interfaces
• Port Channel with 50-Gigabit Ethernet interfaces
• Port Channel with 100-Gigabit Ethernet interfaces
Port Cost:
• 200000
• 20000
• 2000
• 1700
• 1400
• 1200
• 200
• 180000
• 18000
• 1800
• 600
• 1200
• 200
• 180
Port Priority 128
To change these parameters, use the following commands.
• Change the forward-delay parameter.
PROTOCOL SPANNING TREE RSTP mode
Rapid Spanning Tree Protocol (RSTP)
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