3Com 4210 PWR - Page 171

Configuring Leaf Nodes 169
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 proprietary standard to calculate the default path costs of
ports.
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.
When calculating the path cost of an aggregated link, the 802.1D-1998 standard
does not take the number of the ports on the aggregated link into account,
Tab le 122 Specify the standard for calculating path costs
Operation Command Description
Enter system view system-view -
Specify the standard for
calculating the default path
costs of the links connected to
the ports of the switch
stp pathcost-standard {
dot1d-1998 | dot1t | legacy}
Optional
By default, the legace
standard is used to calculate
the default path costs of
ports.
Tab le 123 Transmission speeds and the corresponding path costs
Transmission
speed
Operation mode
(half-/full-duplex)
802.1D-1998 IEEE 802.1t
Proprietary
standard
0 - 65,535 200,000,000 200,000
10 Mbps Half-duplex/Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
100
95
95
95
200,000
1,000,000
666,666
500,000
2,000
1,800
1,600
1,400
100 Mbps Half-duplex/Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
19
15
15
15
200,000
100,000
66,666
50,000
200
180
160
140
1,000 Mbps Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
4
3
3
3
200,000
10,000
6,666
5,000
20
18
16
14
10 Gbps Full-duplex
Aggregated link 2 ports
Aggregated link 3 ports
Aggregated link 4 ports
2
1
1
1
200,000
1,000
666
500
2
1
1
1