Optional) Setting A Path Cost Of A Port In An Msti - Huawei Quidway S7700 Configuration Manual - Ethernet

Quidway S7700 Smart Routing Switch
Configuration Guide - Ethernet
If an S7700 is configured as the root switch or secondary root switch, the priority of the
S7700 cannot be set. If you want to set the priority of the S7700, you must disable the root switch
or secondary root switch.
Procedure
Step 1 Run:
system-view
The system view is displayed.
Step 2 Run:
stp [ instance instance-id ] priority priority
A priority is set for the switching device in an MSTI.
The default priority value of the switching device is 32768.
If the instance is not designated, a priority is set for the switching device in MSTI0.
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9.2.5 (Optional) Setting a Path Cost of a Port in an MSTI

The MSTP path cost determines root port selection in an MSTI. The port with the lowest path
cost to the root bridge is selected as a root port.
Context
A path cost is port-specific, which is used by MSTP as a reference to select a link.
Path costs of a port are an important basis for calculating spanning trees. If you set different path
costs for a port in different MSTIs, you can make VLAN traffic be transmitted along different
physical links and thus carry out VLAN load balancing.
On a network where loops occur, you are recommended to set a relatively large path cost for the
port at a low link rate. MSTP puts the port with the large path cost in the Blocking state and
blocks the link where this port resides.
Procedure
Step 1 Run:
system-view
Issue 01 (2011-07-15)
CAUTION
NOTE
l To configure a switching device as a primary root bridge, you can run the stp [ instance instance-id ]
root primary command directly. The priority value of this switching device is 0.
l To configure a switching device as a secondary root bridge, run the stp [ instance instance-id ] root
secondary command. The priority value of this switching device is 4096.
In an MSTI, a switching device cannot act as a primary root bridge and a secondary root bridge at the
same time.
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