Configuring Path Costs Of Ports - HP 5120 EI Series Lan Switching Configuration Manual

Link speed
10 Gbps
Configuration restrictions and guidelines
When it calculates path cost for an aggregate interface, IEEE 802.1t takes into account the number
•
of Selected ports in its aggregation group, but IEEE 802.1d- 1 998 does not. The calculation formula
of IEEE 802.1t is: Path cost = 200,000,000/link speed (in 100 kbps), where link speed is the sum
of the link speed values of the Selected ports in the aggregation group.
When multiple ports operate at a rate higher than 10 Gbps and the standard for default path cost
•
calculation is dot1d-1998 or legacy, the path cost of a single port or an aggregate interface takes
the smallest value. As a result, the forwarding path selected might not be optimal. To solve this
problem, use dot1t as the standard for default path cost calculation, or manually set the path cost
for a port (see
Configuration procedure
To specify a standard for the device to use when it calculates the default path cost:
Step
1. Enter system view.
2. Specify a standard for the
device to use when it
calculates the default path
costs of its ports.

Configuring path costs of ports

When the path cost of a port changes, the system re-calculates the role of the port and initiates a state
transition.
To configure the path cost of ports:
Step
1. Enter system view.
2. Enter interface view or port
group view.
Port type
Single port
Aggregate interface
containing 2 Selected ports
Aggregate interface
containing 3 Selected ports
Aggregate interface
containing 4 Selected ports
"Configuring path costs of
Command
system-view
stp pathcost-standard
{ dot1d-1998 | dot1t | legacy }
Command
system-view
•
Enter Layer 2 Ethernet interface view or
Layer 2 aggregate interface view:
interface interface-type
interface-number
•
Enter port group view:
port-group manual port-group-name
Path cost
IEEE 802.1d-1998
2
ports").
83
IEEE 802.1t Private standard
2000 2
1000 1
666 1
500 1
Remarks
N/A
Optional.
legacy by default.
Remarks
N/A
Use one of the commands.