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Configuring the switch parameters, Setting the forward time, hello time, and max age, Rstp switch parameters – Allied Telesis AT-8100 Series User Manual

Page 822

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Chapter 56: Rapid Spanning Tree Protocol (RSTP) Procedures

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Configuring the Switch Parameters

This table lists the RSTP parameters that are set in the Global
Configuration mode and apply to all the ports on the switch.

Setting the

Forward Time,

Hello Time, and

Max Age

You should not change the forward time, hello time, and max-age
parameters from their default values unless you are familiar with their
functions. These parameters have to be set in accordance with the
following formulas, as specified in IEEE Standard 802.1d:

max-age <= 2 x (forward time - 1.0 second)
max-age >= 2 x (hello time + 1.0 second)

This example reduces the max-age parameter to discard BPDUs after 10
seconds:

awplus> enable
awplus# configure terminal
awplus(config)# spanning-tree max-age 10

Table 91. RSTP Switch Parameters

To

Use This Command

Range

Specify how long the ports remain in
the listening and learning states
before they transition to the forwarding
state.

SPANNING-TREE FORWARD-TIME
forwardtime

4 to 30
seconds

Configure how frequently the switch
sends spanning tree configuration
information if it is the root bridge or is
trying to become the root bridge.

SPANNING-TREE HELLO-TIME
hellotime

1 to 10 seconds

Configure how long the switch stores
bridge protocol data units (BPDUs)
before deleting them.

SPANNING-TREE MAX-AGE maxage

6 to 40 seconds

Assign the switch a priority number,
which is used to determine the root
bridge in the spanning tree domain.

SPANNING-TREE PRIORITY priority

0 to 61,440, in
increments of
4,096

Enable BPDU guard so that the switch
disables edge ports if they receive
BPDU packets.

SPANNING-TREE PORTFAST
BPDU-GUARD

-

Disable BPDU guard on the switch.

NO SPANNING-TREE PORTFAST
BPDU-GUARD

-