Spanning-tree portfast (stp) – Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) User Manual
Page 547
Spanning Tree Commands
Software Reference for x310 Series Switches
C613-50046-01 REV A
AlliedWare Plus
TM
Operating System - Version 5.4.4C
19.57
spanning-tree portfast (STP)
Use this command in Interface Configuration mode for a switch port interface only to set a
port as an edge-port. The portfast feature enables a port to rapidly move to the
forwarding state, without having first to pass through the intermediate spanning tree
states. This command has the same effect as the
spanning-tree edgeport (RSTP and
command, but the configuration displays differently in the output of some show
commands.
You can obtain the same effect by running the
spanning-tree edgeport (RSTP and
command. However, the configuration output may display differently in some
show commands.
Use the no variant of this command to set a port to its default state (not an edge-port).
Syntax
spanning-tree portfast
no spanning-tree portfast
Default
Not an edge port.
Mode
Interface Configuration mode for a switch port interface only.
Usage
Portfast makes a port move from a blocking state to a forwarding state, bypassing both
listening and learning states. The portfast feature is meant to be used for ports connected
to end-user devices not switches. Enabling portfast on ports that are connected to a
workstation or server allows devices to connect to the network without waiting for
spanning-tree to converge.
For example, you may need hosts to receive a DHCP address quickly and waiting for STP to
converge would cause the DHCP request to time out. Ensure you do not use portfast on
any ports connected to another switch to avoid creating a spanning-tree loop on the
network.
Use this command on a switch port that connects to a LAN with no other bridges
attached. An edge port should never receive BPDUs. Therefore if an edge port receives a
BPDU, the portfast feature takes one of three actions.
■
Cease to act as an edge port and pass BPDUs as a member of a spanning tree network
(
command disabled).
■
Filter out the BPDUs and pass only the data and continue to act as a edge port
(
spanning-tree portfast bpdu-filter
command enabled)
■
Block the port to all BPDUs and data (
spanning-tree portfast bpdu-guard
command enabled).
Note
You can run either of two additional parameters with this command. To
simplify the syntax these are documented as separate commands. See the
following additional portfast commands:
■
spanning-tree portfast bpdu-filter command on page 19.59
■