79
Step Command
Remarks
2.
Set the spanning tree mode.
stp mode
{
stp
|
rstp
|
mstp
|
pvst
}
MSTP mode by default.
Configuring an MST region
Two or more spanning tree devices belong to the same MST region only if they are configured to have the
same format selector (0 by default, not configurable), MST region name, MST region revision level, and
the same VLAN-to-instance mapping entries in the MST region, and each two devices are connected by
a physical link.
Configuration restrictions and guidelines
•
The configuration of MST region–related parameters, especially the VLAN-to-instance mapping
table, will result in a new spanning tree calculation. To reduce the possibility of topology instability,
the MST region configuration takes effect only after you activate it by using the
active
region-configuration
command, or enable a spanning tree protocol by using the
stp enable
command in the case that the spanning tree protocol is disabled.
•
The device in PVST mode automatically maps VLANs to MSTIs, and supports more MSTIs than in
MSTP mode. When you change the spanning tree mode from PVST to MSTP, exceeding
VLAN-to-instance mappings (arranged in ascending order of MSTI IDs) are silently deleted and
cannot be recovered even if you change the spanning tree mode back. To prevent loss of mappings,
do not manually configure VLAN-to-instance mappings in PVST mode.
Configuration procedure
To configure an MST region:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter MST region view.
stp region-configuration
N/A
3.
Configure the MST
region name.
region-name
name
Optional.
The MST region name is the MAC address
by default.
4.
Configure the
VLAN-to-instance
mapping table.
•
instance
instance-id
vlan
vlan-list
•
vlan-mapping modulo
modulo
Optional.
Use either command.
All VLANs in an MST region are mapped
to the CIST (or MSTI 0) by default.
5.
Configure the MSTP
revision level of the MST
region.
revision-level
level
Optional.
0 by default.
6.
Display the MST region
configurations that are
not activated yet.
check region-configuration
Optional.
7.
Activate MST region
configuration manually.
active region-configuration
N/A
