3Com 4200G 12-Port Configuration Manual page 146

132 C 20: MSTP C
HAPTER
Maximum Transmitting
Speed Configuration
Edge Port Configuration
Path Cost Configuration
ONFIGURATION
Refer to "Maximum Transmitting Speed Configuration".
Refer to "Edge Port Configuration".
The path cost parameters reflects the link rates on ports. For a port on an
MSTP-enabled switch, the path cost may differ with spanning tree instance. You can
enable flows of different VLANs to travel along different physical links by configuring
appropriate path costs on ports, so that load balancing can be achieved by VLANs.
The switch can automatically calculate the path costs of ports, but you can also
manually configure them.
Standards for calculating path costs of ports
Currently, a switch 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 standard defined by 3Com to calculate the default path costs
■
of ports.
Table 103 Specify the standard for calculating path costs
Operation
Enter system view
Specify the standard to
be used to calculate
the default path costs
of the links connected
to the switch
Table 104 Transmission speeds and the corresponding path costs
Transmiss Operation mode
ion speed (half-/full-duplex)
0 —
10 Mbps Half-duplex
Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
100 Mbps Half-duplex
Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
1,000 Full-duplex
Mbps
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
Command
system-view
stp pathcost-standard
{ dot1d-1998 | dot1t | legacy }
802.1D-1998
65,535
100
99
95
95
95
19
18
15
15
15
4
3
3
3
Description
—
Optional
By default, the legacy standard is
used to calculate the default path
costs of ports.
Standard
IEEE 802.1t defined by 3Com
200,000,000 200,000
2,000,000 2,000
1,999,999 2,000
1,000,000 1,800
666,666 1,600
500,000 1,400
200,000 200
199,999 200
100,000 180
66,666 160
50,000 140
20,000 20
10,000 18
6,666 16
5,000 14