Allied-telesis AT-9000 Series Instrukcja Użytkownika Pobierz pdf (Strona 150)

Chapter 13: Setting Switch Spanning Tree Protocols

150

The range is 0 to 61,440, in increments of 4,096. The range is

divided into the sixteen increments listed in Table 1. You specify

the increment that represents the desired bridge priority value. The

default value is 32,768 (increment 8).

Note

Set the hello time, forward delay, and max-age fields according to

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)

 Hello Time— Frequency that the switch sends spanning tree

configuration information when it is the root bridge or is trying to

become the root bridge.

 Forward Delay— Forward time parameter on the switch. This field

specifies how long the ports remain in the listening and learning

states before they transition to the forwarding state.

The Forward Delay value is active only when the switch is acting

as the root bridge of the spanning tree domain. Switches that are

not acting as the root bridge use a dynamic value supplied by the

root bridge.

 Max Age— How long bridge protocol data units (BPDUs) are

stored by the switch before they are deleted.

Table 1. STP Bridge Priority Value Increments

Increment

Bridge

Priority

Increment

Bridge

Priority

00832768

1 4096 9 36864

2 8192 10 40960

3 12288 11 45056

4 16384 12 49152

5 20480 13 53248

6 24576 14 57344

7 28672 15 61440

1 2 ... 145 146 147 148 149 150 151 152 153 154 155 ... 257 258

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Allied-telesis AT-9000 Series Instrukcja Użytkownika Strona 150