HP 5820X Series

79
Path cost
Link speed Port type
IEEE 802.1d-1998 IEEE 802.1t Private standard
Aggregate interface
containing 4 selected ports
500,000 1400
Single Port 200,000 200
Aggregate interface
containing 2 selected ports
100,000 180
Aggregate interface
containing 3 selected ports
66,666 160
100 Mbps
Aggregate interface
containing 4 selected ports
19
50,000 140
Single Port 20,000 20
Aggregate interface
containing 2 selected ports
10,000 18
Aggregate interface
containing 3 selected ports
6666 16
1000 Mbps
Aggregate interface
containing 4 selected ports
4
5000 14
Single Port 2000 2
Aggregate interface
containing 2 selected ports
1000 1
Aggregate interface
containing 3 selected ports
666 1
10 Gbps
Aggregate interface
containing 4 selected ports
2
500 1
When calculating path cost for an aggregate interface, IEEE 802.1d-1998 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... Use the command... Remarks
1. Enter system view
system-view —
Enter Ethernet interface
view or Layer 2
aggregate interface view
interface interface-type
interface-number
2. Enter
interface
view or port
group view
Enter port group view
port-group manual port-
group-name
Required.
Use either command.
3. Configure the path cost of the ports
stp [ instance instance-id ]
cost cost
Required.
By default, MSTP
automatically calculates the
path cost of each port.