HP 5820X series Configuration Manual page 86

Link speed
100 Mbps
1000 Mbps
10 Gbps
When calculating path cost for an aggregate interface, IEEE 802.1d- 1 998 does not take into account the
number of selected ports in its aggregation group as IEEE 802.1t does. 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.
Configuring path costs of ports
To configure the path cost of ports:
To do...
1. Enter system view
2. Enter
interface
view or port
group view
3. Configure the path cost of the ports
Port type
Aggregate interface
containing 4 selected ports
Single Port
Aggregate interface
containing 2 selected ports
Aggregate interface
containing 3 selected ports
Aggregate interface
containing 4 selected ports
Single Port
Aggregate interface
containing 2 selected ports
Aggregate interface
containing 3 selected ports
Aggregate interface
containing 4 selected ports
Single Port
Aggregate interface
containing 2 selected ports
Aggregate interface
containing 3 selected ports
Aggregate interface
containing 4 selected ports
Enter Ethernet interface
view or Layer 2
aggregate interface view
Enter port group view
Path cost
IEEE 802.1d-1998 IEEE 802.1t
500,000
200,000
100,000
19
66,666
50,000
20,000
10,000
4
6666
5000
2000
1000
2
666
500
Use the command...
system-view
interface interface-type
interface-number
port-group manual port-
group-name
stp [ instance instance-id ]
cost cost
79
Private standard
1400
200
180
160
140
20
18
16
14
2
1
1
1
Remarks
—
Required.
Use either command.
Required.
By default, MSTP
automatically calculates the
path cost of each port.