Stp Root-Protection - 3Com Switch 4500 Family Manual

Parameters
instance-id: MSTI ID ranging from 0 to 16. The value of 0 refers to the CIST.
bridgenum: Network diameter of the specified spanning tree. This argument ranges from 2 to 7 and
defaults to 7.
centi-seconds: Hello time in centiseconds of the specified spanning tree. This argument ranges from
100 to 1,000 and defaults to 200.
Description
Use the stp root secondary command to configure the current switch as a secondary root bridge of a
specified MSTI.
Use the undo stp root command to cancel the current configuration.
By default, a switch does not operate as a secondary root bridge.
If you do not specify the instance-id argument, the two commands apply to only the CIST.
You can configure one or more secondary root bridges for an MSTI. If the switch operating as the root
bridge fails or is turned off, the secondary root bridge with the least MAC address becomes the root
bridge.
You can specify the network diameter and the hello time of the switch when you are configuring it as a
secondary root bridge. The switch will then figure out the other two time parameters: forward delay and
max age. If the instance-id argument is specified to 0 in this command, the current switch is configured
as the secondary root bridge of the CIST. You can configure only one root bridge for an MSTI but you
can configure one or more secondary root bridges for an MSTI.
Once a switch is configured as the root bridge or a secondary root bridge, its priority cannot be modified.
Examples
# Configure the current switch as a secondary root bridge of MSTI 4, setting the network diameter of the
switched network to 5 and the hello time of the current switch to 300 centiseconds.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] stp instance 4 root secondary bridge-diameter 5 hello-time 300

stp root-protection

Syntax
Ethernet port view:
stp root-protection
undo stp root-protection
System view:
stp interface interface-list root-protection
undo stp interface interface-list root-protection
View
System view, Ethernet port view
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