Brocade Mobility RFS7000-GR Controller CLI Reference Guide (Supporting software release 4.1.0.0-040GR and later) - Manual (Page 243)

Brocade Mobility RFS7000-GR Controller CLI Reference Guide 229
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Global Configuration Commands
5
Usage Guidelines
The
mst > configuration
command moves you to the Spanning tree-mst Instance instance.
If a bridge does not hear bridge protocol data units (BPDUs) from the root bridge within the
specified interval defined in the max-age (seconds) parameter, assume the network has changed
and recompute the spanning-tree topology.
Example
RFS7000(config)#spanning-tree portfast bpduguard default
RFS7000(config)#
•
forward-time <4-30> – Sets the time (in seconds) after which (if this bridge is
the root bridge) each port changes states to learning and forwarding. This value
is used by all instances. The default value is 15 seconds.
•
hello-time <1-10> – Sets the hello-time. The hello-time is the time in seconds
after which (if this bridge is the root bridge) all the bridges in a bridged LAN
exchange Bridge Protocol Data Units (BPDUs). A very low value leads to
excessive traffic on the network, while a higher value delays the detection of
topology change. This value is used by all instances. The default value is 2
seconds.
•
max-age <6-40> – Max-age is the maximum time in seconds for which (if a
bridge is the root bridge) a message is considered valid. This prevents the
frames from looping indefinitely. The value must be greater than twice the
value of the hello time plus one, but less than twice the value of the forward
delay minus one.
The allowable range for max-age is 6-40 seconds. Configure this value
sufficiently high, so that a frame generated by root can be propagated to the
leaf nodes without exceeding the max-age. Use this command to set the
max-age for a bridge. This value is used by all instances.
The default value of bridge max-age is 20 seconds.
•
max-hops <7-127> – Specifies the maximum allowed hops for a BPDU in an
MST region. This parameter is used by all MST instances. To restore the default
value, use the no parameter with this command. The default max-hops in a
MST region is 20.
portfast
[bpdufilter|bpduguard](defa
ult) Enables the portfast feature on a bridge. It has the following options:
•
bpdufilter (default) – Use the bpdu-filter command to set the portfast
BPDU filter for the port. Use the no parameter with this command to revert the
port BPDU filter value to default.
The Spanning Tree Protocol sends BPDUs from all ports. Enabling the BPDU
Filter feature ensures PortFast enabled ports do not transmit or receive BPDUs.
•
bpduguard (default) – Use the
bpdu-guard
command to enable the BPDU
(Bridge Protocol Data Unit) Guard feature on a bridge.
Use the
no parameter with this command to disable BPDU Guard.
When the BPDU Guard is set for a bridge, all portfast-enabled ports that have
the bpdu guard set to default shut down the port on receiving a BPDU. In this
case, the BPDU is not processed. The port can be brought back up manually
(using the no shutdown command), or by configuring a errdisable-timeout to
enable the port after the specified interval.