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spanning-tree 0 priority priority-value
The range is from 0 to 15.
The default is 8.
To view the current values for interface parameters, use the show spanning-tree 0 command from
EXEC privilege mode. Refer to the second example in Enabling Spanning Tree Protocol Globally.
Enabling PortFast
The PortFast feature enables interfaces to begin forwarding traffic approximately 30 seconds sooner.
Interfaces forward frames by default until they receive a BPDU that indicates that they should behave
otherwise; they do not go through the Learning and Listening states. The bpduguard shutdown-on-
violation option causes the interface hardware to be shut down when it receives a BPDU. When you
only implement bpduguard, 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
BPDU violation. BPDUs are dropped in the software after receiving the BPDU violation.
PDU Filtering enabled on an interface stops sending and receiving BPDUs on the port fast enabled ports.
When you enable BPDU guard and BPDU filter on the port, then BPDU filter takes the highest
precedence. By default BPDU filtering on an interface is disabled.
CAUTION: Enable PortFast only on links connecting to an end station. PortFast can cause loops if
it is enabled on an interface connected to a network.
To enable PortFast on an interface, use the following command.
• Enable PortFast on an interface.
INTERFACE mode
spanning-tree stp-id portfast [bpduguard | [shutdown-on-violation] |
bpdufilter]
Example of Verifying PortFast is Enabled on an Interface
To verify that PortFast is enabled on a port, use the show spanning-tree command from EXEC
Privilege mode or the show config command from INTERFACE mode. Dell Networking recommends
using the
show config command.
Dell#(conf-if-te-1/1)#show conf
!
interface Tengigabitethernet 1/1
no ip address
switchport
spanning-tree 0 portfast
no shutdown
Dell#(conf-if-te-1/1)#
Spanning Tree Protocol (STP)
917