Huawei Quidway S3100 Series Operation Manual page 183

Operation Manual – MSTP
Quidway S3100 Series Ethernet Switches
Table 1-22 Transmission speeds and the corresponding path costs
Transm
ission
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.
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
Enter system view
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
Command
system-view
Huawei Technologies Proprietary
802.1D-1998 IEEE 802.1t
65,535 200,000,000
100 2,000,000
99 1,999,999
95 1,000,000
95 666,666
95 500,000
19 200,000
18 199,999
15 100,000
15 66,666
15 50,000
4 20,000
3 10,000
3 6,666
3 5,000
2 2,000
1 1,000
1 666
1 500
—
1-27
Chapter 1 MSTP Configuration
Standard
defined by
Huawei-3Com
200,000
2,000
2,000
1,800
1,600
1,400
200
200
180
160
140
20
18
16
14
2
1
1
1
Description