H3C S3100-52P, Руководство по эксплуатации

Страница: 24 / 62

Operation Manual – MSTP
H3C S3100-52P Ethernet Switch
Chapter 1 MSTP Configuration
1-22
2 20 to 30
1.3.3 Specifying the Current Switch as a Root Bridge/Secondary Root Bridge
MSTP can automatically choose a switch as a root bridge through calculation. You can
also manually specify the current switch as a root bridge by using the corresponding
commands.
I. Specify the current switch as the root bridge of a spanning tree
Follow these steps to specify the current switch as the root bridge of a spanning tree:
To do... Use the command... Remarks
Enter system view
system-view
—
Specify the current switch
as the root bridge of a
spanning tree
stp
[
instance instance-id
]
root
primary
[
bridge-diameter
bridgenumber
[
hello-time
centi-seconds
] ]
Required
II. Specify the current switch as the secondary root bridge of a spanning tree
Follow these steps to specify the current switch as the secondary root bridge of a
spanning tree:
To do... Use the command... Remarks
Enter system view
system-view
—
Specify the current switch
as the secondary root
bridge of a specified
spanning tree
stp
[
instance instance-id
]
root
secondary
[
bridge-diameter
bridgenumber
[
hello-time
centi-seconds
] ]
Required
Using the
stp root primary
/
stp root secondary
command, you can specify the current
switch as the root bridge or the secondary root bridge of the MSTI identified by the
instance-id
argument. If the value of the
instance-id
argument is set to 0, the
stp root
primary
/
stp root secondary
command specify the current switch as the root bridge or
the secondary root bridge of the CIST.
A switch can play different roles in different MSTIs. That is, it can be the root bridges in
an MSTI and be a secondary root bridge in another MSTI at the same time. But in the
same MSTI, a switch cannot be the root bridge and the secondary root bridge
simultaneously.
When the root bridge fails or is turned off, the secondary root bridge becomes the root
bridge if no new root bridge is configured. If you configure multiple secondary root
bridges for an MSTI, the one with the smallest MAC address replaces the root bridge
when the latter fails.