DIS-200G Series Gigabit Ethernet Switch CLI Reference Guide
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spanning-tree portfast
This command is used to specify the port’s fast mode. Use the
no
form of this command to revert to the default
setting.
spanning-tree portfast {disable | edge| network}
no spanning-tree portfast
Parameters
Default
By default, this option is edge.
Command Mode
Interface Configuration Mode.
Command Default Level
Level: 15.
Usage Guideline
A port can be in one of the following three port fast modes:
Edge mode -
The port will directly change to the spanning-tree forwarding state when a link-up occurs
without waiting for the forward-time delay. If the interface receives a BPDU later, its operation state
changes to the non-port-fast state.
Disable mode -
The port will always be in the non-port-fast state. It will always wait for the forward-time
delay to change to forwarding state.
Network mode -
The port will remain in the non-port-fast state for three seconds. The port will change
to the port-fast state if no BPDU is received and changes to the forwarding state. If the port received the
BPDU later, it will change to the non-port-fast state
This command should be used with caution. Otherwise, an accidental topology loop and data-packet loop may
be generated and disrupt the network operation.
Example
This example shows how to configure port Ethernet 1/0/1 to the port-fast network mode.
Switch# configure terminal
Switch(config)# interface Ethernet 1/0/1
Switch(config-if)# spanning-tree portfast network