Stp Cost - HP 5900 series Command Reference Manual

Related commands
display stp
•
stp global config-digest-snooping
•

stp cost

Use stp cost to set the path cost of the port or ports.
Use undo stp cost to restore the default.
Syntax
stp [ instance instance-list ] cost cost
undo stp [ instance instance-list ] cost
Default
The device automatically calculates the path costs of ports in each spanning tree based on the
corresponding standard.
Views
Ethernet interface view, aggregate interface view
Predefined user roles
network-admin
Parameters
instance instance-list: Sets the path cost of the ports in the MSTIs that are specified by an instance list, in
the format of instance-list = { instance-id [ to instance-id ] }&<1- 1 0>, where &<1- 1 0> indicates that you
can specify up to 10 instances or instance ranges. The instance-id argument ranges from 0 to 4094, and
the value 0 represents the CIST.
cost: Specifies the path cost of the port, with an effective range that depends on the path cost calculation
standard that is adopted.
When the IEEE 802.1d- 1 998 standard is selected for path cost calculation, the cost argument
•
ranges from 1 to 65535.
• When the IEEE 802.1t standard is selected for path cost calculation, the cost argument ranges from
1 to 200000000.
When the private standard is selected for path cost calculation, the cost argument ranges from 1 to
•
200000.
Usage guidelines
Path cost is an important factor in spanning tree calculation. Setting different path costs for a port in
MSTIs allows VLAN traffic flows to be forwarded along different physical links, which results in
VLAN-based load balancing.
The path cost setting of a port can affect the role selection of the port. When the path cost of a port is
changed, the system calculates the role of the port and initiates a state transition.
When the setting is configured in Ethernet interface view, it takes effect on only that interface.
When the setting is configured in aggregate interface view, it takes effect on only the aggregate
interface.
When the setting is configured on a member port in an aggregation group, is takes effect only after the
port leaves the aggregation group.
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