Spanning-tree portfast – Brocade Network OS Command Reference v4.1.0 User Manual

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Network OS Command Reference

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spanning-tree portfast

Enables the Port Fast feature on an interface to allow the interface to quickly transition to
forwarding state.

Synopsis

spanning-tree portfast [bpdu-filter | bpdu-guard]

Operands

bpdu-filter

Sets the Port Fast BPDU filter for the port.

bpdu-guard

Guards the port against the reception of BPDUs.

Defaults

Port Fast is disabled.

Command Modes

Interface subtype configuration mode

Description

Use this command to enable the Port Fast feature. This command is the only for the Spanning Tree
Protocol (STP). Port Fast immediately puts the interface into the forwarding state without having to
wait for the standard forward time. Use the spanning-tree edgeport command for MSTP and RSTP.

BPDU filter prevents the switch from sending BPDU frames on ports that are enabled with portfast.

BPDU guard disables all portfast-enabled ports should they ever receive BPDU frames. It does not
prevent transmitting of BPDU frames.

Usage Guidelines

If you enable spanning-tree portfast bpdu-guard on an interface and the interface receives a
BPDU, the software disables the interface and puts the interface in the ERR_DISABLE state.

Enable Port Fast on ports connected to host. Enabling Port Fast on interfaces connected to
switches, bridges, hubs, and so on can cause temporary bridging loops, in both trunking and
nontrunking mode.

If xSTP is enabled over VCS, this command must be executed on all RBridge nodes.

Examples

To enable a port to quickly transition to the forwarding state:

switch(config)# interface tengigabitethernet 0/1

switch(conf-if-te-0/1)# spanning-tree portfast

To set the Port Fast BPDU filter for the port:

switch(config)# interface tengigabitethernet 0/1

switch(conf-if-te-0/1)# spanning-tree portfast bpdu-filter

To guard the port against the reception of BPDUs:

switch(config)# interface tengigabitethernet 0/1

switch(conf-if-te-0/1)# spanning-tree portfast bpdu-guard