User Manual
UMN:CLI
V8102
381
9.4.7.2
Root Switch
To establish MSTP function, a root switch should be chosen first. In MSTP, a root switch
is called as IST root switch. Each switch has its own bridge ID, and one of the switchs on
same LAN is chosen as a root switch by comparing with their bridge IDs. However, you
can configure the priority and make it more likely that the switch will be chosen as the root
switch. The switch having the lowest priority becomes the root switch.
To configure the priority for an MSTP instance number, use the following command.
Command
Mode
Description
spanning-tree mst
<0-64>
priority
<0-61440>
Global
Configures the priority of the switch:
0-64: MSTP instance ID number.
0-61440: priority value in increments of
4096 (default: 32768)
no spanning-tree mst
<0-64>
priority
Clears the Priority of the switch, enter the
instance number.
If you configure a priority of STP or RSTP in the V8102, you should configure MSTP in-
stance ID number as 0.
9.4.7.3
Path-cost
After deciding a root swich, you need to decide to which route you will forward the packet.
To do this, the standard is a path-cost. By the path-cost of root port, you can configure a
route manually. To configure the path-cost value for specified instance number in MSTP,
use the following command.
Command
Mode
Description
spanning-tree mst
<0-64>
cost
<1-200000000>
Interface
[XE/GE]
Configures path-cost for specified MSTP
instance number:
0-64: MSTP instance ID number.
1-200000000: the path cost value.
no spanning-tree mst
<0-64>
cost
Deletes a configured path-cost.
9.4.7.4
Port Priority
When all conditions of two routes of switch are same, the last standard to decide a route
is port-priority. You can configure port priority and select a route manually.
To configure a port priority for MSTP instance, use the following command.
Command
Mode
Description
spanning-tree mst
<0-64>
in-
terface-priority
<0-240>
Interface
[XE/GE]
Configures the port priority of MSTP instance.
0-64: MSTP instance ID number.
0-240: port priority in increments of 16 (default:128)
no spanning-tree mst
<0-64>
interface-priority
Deletes a configured port priority of MSTP instance.
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