H3C Technologies H3C S7500E Series Switches - Manual (Page 179)

13-27
Configuring Path Costs of Ports
Path cost is a parameter related to the rate of a port. On an MSTP-enabled device, a port can have
different path costs in different MSTIs. Setting appropriate path costs allows VLAN traffic flows to be
forwarded along different physical links, thus achieving VLAN-based load balancing.
The device can automatically calculate the default path cost; alternatively, you can also configure the
path cost for ports.
Make the following configurations on the leaf nodes only.
Specifying a standard that the device uses when calculating the default path cost
You can specify a standard for the device to use in automatic calculation for the default path cost. The
device supports the following standards:
dot1d-1998 : The device calculates the default path cost for ports based on IEEE 802.1d-1998.
dot1t : The device calculates the default path cost for ports based on IEEE 802.1t.
legacy : The device calculates the default path cost for ports based on a private standard.
Follow these steps to specify a standard for the device to use when calculating the default path cost:
To do... Use the command... Remarks
Enter system view system-view —
Specify a standard for the
device to use when calculating
the default path costs of its ports
stp pathcost-standard
{ dot1d-1998 | dot1t | legacy }
Optional
By default, the device calculates the
default path cost for ports based on a
private standard.
Table 13-7 Link speed vs. path cost
Link speed Duplex state 802.1d-1998 802.1t Private standard
0 — 65535 200,000,000 200,000
10 Mbps
Single Port
Aggregate Link 2 Ports
Aggregate Link 3 Ports
Aggregate Link 4 Ports
100
100
100
100
2,000,000
1,000,000
666,666
500,000
2,000
1,800
1,600
1,400
100 Mbps
Single Port
Aggregate Link 2 Ports
Aggregate Link 3 Ports
Aggregate Link 4 Ports
19
19
19
19
200,000
100,000
66,666
50,000
200
180
160
140
1000 Mbps
Single Port
Aggregate Link 2 Ports
Aggregate Link 3 Ports
Aggregate Link 4 Ports
4
4
4
4
20,000
10,000
6,666
5,000
20
18
16
14