Adding an Interface to the Spanning Tree Group
To add a Layer 2 interface to the spanning tree topology, use the following command.
•
Enable spanning tree on a Layer 2 interface.
INTERFACE mode
spanning-tree 0
Modifying Global Parameters
You can modify the spanning tree 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 STP.
NOTE:
Dell Networking recommends that only experienced network administrators change the spanning tree parameters. Poorly
planned modification of the spanning tree parameters can negatively affect network performance.
The following table displays the default values for STP.
Table 86. STP Default Values
STP Parameters
Forward Delay
Hello Time
Max Age
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 Priority
•
Change the forward-delay parameter (the wait time before the interface enters the Forwarding state).
PROTOCOL SPANNING TREE mode
forward-delay seconds
The range is from 4 to 30.
The default is 15 seconds.
•
Change the hello-time parameter (the BPDU transmission interval).
818
Spanning Tree Protocol (STP)
Default Value
15 seconds
2 seconds
20 seconds
•
200000
•
20000
•
2000
•
1700
•
1400
•
1200
•
200
•
180000
•
18000
•
1800
•
600
•
1200
•
200
•
180
8