Operation Manual – MSTP
Quidway S3100 Series Ethernet Switches
Chapter 1 MSTP Configuration
Huawei Technologies Proprietary
1-27
Table 1-22
Transmission speeds and the corresponding path costs
Transm
ission
speed
Operation mode
(half-/full-duplex)
802.1D-1998
IEEE 802.1t
Standard
defined by
Huawei-3Com
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
99
95
95
95
2,000,000
1,999,999
1,000,000
666,666
500,000
2,000
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
18
15
15
15
200,000
199,999
100,000
66,666
50,000
200
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
20,000
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
2,000
1,000
666
500
2
1
1
1
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, whereas the
802.1T standard does. The following formula is used to calculate the path cost of an
aggregated link:
Path cost = 200,000,000 / link transmission speed
Here the link transmission speed is the sum of the speeds of the unblocked ports on the
aggregated link, which is measured in 100 Kbps.
II. Configuring the path costs of ports
Table 1-23
Configure the path cost for specified ports in system view
Operation
Command
Description
Enter system view
system-view
—