The instance command maps a VLAN to a spanning tree instance.
The undo instance command deletes the mapping between a VLAN and a spanning tree instance.
By default, all VLANs are mapped to CIST, that is, instance 0.
instance instance-id vlan { vlan-id1 [ to vlan-id2 ] } &<1-10>
undo instance instance-id [ vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ]
| Parameter | Description | Value |
|---|---|---|
instance-id |
Specifies the number of a spanning tree instance. |
The value is an integer ranging from 0 to 4094. Value 0 refers to CIST. NOTE:
instance-id ranges from 0 to 4094. Each process supports a maximum of 65 instances. |
vlan vlan-id1 |
Specifies a start VLAN ID. |
The value is an integer ranging from 1 to 4094. The start VLAN ID must be smaller than the end VLAN ID. |
to vlan-id2 |
Specifies an end VLAN ID. NOTE:
|
The value is an integer that ranges from 1 to 4094. |
Usage Scenario
MSTP divides a switching network into multiple regions, each of which has multiple spanning trees that are independent of each other. Each spanning tree is called an MSTI and each region is called an MST region.
The instance command is used to set mappings between spanning tree instances and VLANs.
Precautions
When using the undo instance command, note the following points:
After the mapping between specified VLANs and a specified spanning tree instance is deleted, these VLANs will be mapped to a CIST, namely, instance 0.
If no VLAN is specified, all VLANs that have established mappings with the spanning tree instance will be mapped to a CIST.
If the instance command is run more than once, all configurations take effect.
A VLAN cannot be mapped to different spanning tree instances. If the instance command is run several times, the latest configuration overrides the previous one.
To map the MUX VLAN to a spanning tree instance, you are advised to configure the principal VLAN, subordinate group VLAN, and subordinate separate VLAN in the MUX VLAN in the same spanning tree instance.