3Com WX3000 Series Operation Manual page 201

Configuring the Path Cost for a Port
The path cost parameter reflects the rate of the link connected to the port. For a port on an
MSTP-enabled device, the path cost may be different in different spanning tree instances. You can
enable flows of different VLANs to travel along different physical links by configuring appropriate path
costs on ports, so that VLAN-based load balancing can be implemented.
Path cost of a port can be determined by the device or through manual configuration.
Standards for calculating path costs of ports
Currently, the device can calculate the path costs of ports based on one of the following standards:
dot1d-1998: Adopts the IEEE 802.1D-1998 standard to calculate the default path costs of ports.
dot1t: Adopts the IEEE 802.1t standard to calculate the default path costs of ports.
legacy: Adopts the proprietary standard to calculate the default path costs of ports.
Follow these steps to specify the standard for calculating path costs:
To do...
Enter system view
Specify the standard for
calculating the default path
costs of the links connected to
the ports of the device
Table 1-7 Transmission speeds and the corresponding path costs
Transmissio
n speed
0
10 Mbps
100 Mbps
1,000 Mbps
10 Gbps
Normally, the path cost of a port operating in full-duplex mode is slightly less than that of the port
operating in half-duplex mode.
Use the command...
system-view
stp pathcost-standard
{ dot1d-1998 | dot1t | legacy }
Operation mode
(half-/full-duplex)
—
Half-duplex/Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
Half-duplex/Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
802.1D-1998 IEEE 802.1t
65,535 200,000,000
100 200,000
95 1,000,000
95 666,666
95 500,000
19 200,000
15 100,000
15 66,666
15 50,000
4 200,000
3 10,000
3 6,666
3 5,000
2 200,000
1 1,000
1 666
1 500
1-31
Remarks
—
Optional
By default, the legacy standard
is used to calculate the default
path costs of ports.
Proprietary
standard
200,000
2,000
1,800
1,600
1,400
200
180
160
140
20
18
16
14
2
1
1
1