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Scaling the Spanning Tree Protocol

187

The command to configure the Spanning Tree Protocol (STP) is

set

spantree

. The following switch output (from our Catalyst 5000) shows the

different command parameters you can use when configuring the Spanning
Tree Protocol. We are interested in the

set spantree root

and

set

spantree secondary

commands at this point:

Todd5000> (enable)

set spantree ?

Set spantree commands:

----------------------------------------------------------------------

set spantree backbonefast Enable or disable fast convergence

set spantree disable Disable spanning tree

set spantree enable Enable spanning tree

set spantree fwddelay Set spantree forward delay

set spantree hello Set spantree hello interval

set spantree help Show this message

set spantree maxage Set spantree max aging time

set spantree multicast-address Set multicast address type for trbrf's

set spantree portcost Set spantree port cost

set spantree portfast Set spantree port fast start

set spantree portpri Set spantree port priority

set spantree portstate Set spantree logical port state

set spantree portvlancost Set spantree port cost per vlan

set spantree portvlanpri Set spantree port vlan priority

set spantree priority Set spantree priority

set spantree root Set switch as primary or secondary root

set spantree uplinkfast Enable or disable uplinkfast groups

Todd5000> (enable)

The

set spantree root

command sets the primary root bridge for a spe-

cific VLAN, or even for all your VLANs. The

set spantree root

secondary

command allows you to configure a backup root bridge.

In the following switch output, notice the options that are available with

the

set spantree root

command:

Todd5000> (enable)

set spantree root ?

Usage: set spantree root [secondary] <vlans> [dia <network_diameter>]

[hello <hello_time>]

(vlans = 1..1005, network_diameter = 2..7, hello_time = 1..10)

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