NOTE
l
The VLAN-to-instance mappings generated using the
vlan-mapping modulo
modulo
commands
cannot meet network requirements. It is recommended that you run the
instance
instance-id
vlan
{
vlan-id1
[
to
vlan-id2
] }&<1-10> command to configure VLAN-to-instance mappings.
l
The
vlan-mapping modulo
specifies the formula (VLAN ID-1)%1. In the formula, (VLAN
ID-1)%modulo means the remainder of (VLAN ID-1) divided by the value of modulo. This formula
is used to map a VLAN to the corresponding MSTI. The calculation result of the formula is the ID of
the mapping MSTI.
Step 5
(Optional) Run:
revision-level
level
The MSTP revision number is set.
By default, the MSTP revision number is 0.
If the revision number of the MST region is not 0, this step is necessary.
NOTE
Changing MST region configurations (especially change of the VLAN mapping table) triggers spanning
tree recalculation and causes route flapping. Therefore, after configuring an MST region name, VLAN-to-
instance mappings, and an MSTP revision number, run the
check region-configuration
command in the
MST region view to verify the configuration. After confirming the region configurations, run the
active
region-configuration
command to activate MST region configurations.
Step 6
Run:
active region-configuration
MST region configurations are activated so that the configured region name, VLAN-to-instance
mappings, and revision number can take effect.
If this step is not done, the preceding configurations cannot take effect.
If you have changed MST region configurations on the switching device after MSTP starts, run
the
active region-configuration
command to activate the MST region so that the changed
configurations can take effect.
----End
8.3.4 (Optional) Configuring a Priority for a Switching Device in an
MSTI
A switching device with a high priority is more likely to be selected as the root bridge in an
MSTI. A smaller priority value indicates a higher priority.
Context
In an MSTI, there is only one root bridge, which is the logic center of the MSTI. During root
bridge selection, a high-performance switching device at a high network layer should be selected
as the root bridge; however, the priority of such a device may not be the highest on the network.
It is therefore necessary to set a high priority for the switching device to ensure that the device
functions as a root bridge.
Low-performance devices at lower network layers are not fit to serve as a root bridge. Therefore,
set low priorities for these devices.
Huawei AR3200 Series Enterprise Routers
Configuration Guide - LAN
8 MSTP Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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