3Com Switch 4800G 24-Port Configuration Manual page 225

Configuring the
Maximum Transmission
Rate of Ports
Configuring Ports as
Edge Ports
Configuring Path Costs
of Ports
Refer to "Configuring the Maximum Transmission Rate of Ports" on page 220 in
the section about root bridge configuration.
Refer to "Configuring Ports as Edge Ports" on page 221 in the section about root
bridge configuration.
Path cost is a parameter related to the rate of port-connected links. On an
MSTP-compliant device, ports can have different priorities in different MST
instances. Setting an appropriate path cost allows VLAN traffic flows to be
forwarded along different physical links, thus to enable per-VLAN load balancing.
The device can automatically calculate the default path cost; alternatively, you can
also configure the path cost for ports.
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...
Enter system view
Specify a standard for the device to use
when calculating the default path cost of
the link connected with the device
Table 43 Link speed vs. path cost
Link speed Duplex state
0 -
10 Mbps Single Port
Aggregated Link 2 Ports
Aggregated Link 3 Ports
Aggregated Link 4 Ports
100 Mbps Single Port
Aggregated Link 2 Ports
Aggregated Link 3 Ports
Aggregated Link 4 Ports
Configuring Leaf Nodes
Use the command...
system-view
stp pathcost-standard
{ dot1d-1998 | dot1t |
legacy }
802.1d-1998 802.1t
65535 200,000,000
100 2,000,000
100 1,000,000
100 666,666
100 500,000
19 200,000
19 100,000
19 66,666
19 50,000
225
Remarks
-
Optional
legacy by default
Private standard
200,000
2,000
1,800
1,600
1,400
200
180
160
140