H3C Technologies H3C S5120 Series Switches - Manual (Page 191)

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Configuring Port Priority
The priority of a port is an important factor in determining whether the port can be elected as the root
port of a device. If all other conditions are the same, the port with the highest priority will be elected as
the root port.
On an MSTP-enabled device, a port can have different priorities in different MSTIs, and the same port
can play different roles in different MSTIs, so that data of different VLANs can be propagated along
different physical paths, thus implementing per-VLAN load balancing. You can set port priority values
based on the actual networking requirements.
Make this configuration on the leaf nodes only.
Follow these steps to configure the priority of a port or a group of ports:
To do... Use the command... Remarks
Enter system view system-view —
Enter Layer 2 Ethernet
port view, or Layer 2
aggregate port view
interface interface-type
interface-number
Enter port
view or port
group view
Enter port group view
port-group manual
port-group-name
Required
Use either command.
Configure the port priority
stp [ instance
instance-id
] port priority
priority
Optional
128 for all ports by default.
z
When the priority of a port is changed, MSTP will re-calculate the role of the port and initiate a state
transition.
z
Generally, a lower priority value indicates a higher priority. If you configure the same priority value
for all the ports on a device, the specific priority of a port depends on the index number of the port.
A lower index number means a higher priority. Changing the priority of a port triggers a new
spanning tree calculation process.
Configuring the Link Type of Ports
A point-to-point link is a link directly connecting two devices. If the two ports across a point-to-point link
are root ports or designated ports, the ports can rapidly transition to the forwarding state after a
proposal-agreement handshake process.
Make this configuration on the root bridge and on the leaf nodes separately.
Follow these steps to configure the link type of a port or a group of ports:
To do... Use the command... Remarks
Enter system view
system-view
—