(Optional) Setting a Path Cost for a Port
Context
Path cost is the reference value used for link selection on an STP/RSTP network.
The path cost value range is determined by the calculation method. After the calculation method is determined, it is recommended that you set smaller path cost values for the ports with higher link rates.
Link Rate |
Recommended Path Cost |
Recommended Path Cost Range |
Allowable Path Cost Range |
|---|---|---|---|
10 Mbit/s |
2000 |
200 to 20000 |
1 to 200000 |
100 Mbit/s |
200 |
20 to 2000 |
1 to 200000 |
1 Gbit/s |
20 |
2 to 200 |
1 to 200000 |
10 Gbit/s |
2 |
2 to 20 |
1 to 200000 |
Over 10 Gbit/s |
1 |
1 to 2 |
1 to 200000 |
If a network has loops, it is recommended that you set a large path cost for ports with low link rates so that STP/RSTP blocks these ports.
Procedure
- Run:
system-viewThe system view is displayed.
- (Optional) Run:
stp pathcost-standard { dot1d-1998 | dot1t | legacy }
A path cost calculation method is specified.
By default, the IEEE 802.1t standard (dot1t) is used to calculate the path costs.
All switching devices on a network must use the same path cost calculation method.
- Run:
interface interface-type interface-number
The view of an interface participating in STP calculation is displayed.
- Run:
stp cost cost
A path cost is set for the interface.
- When the Huawei calculation method is used, cost ranges from 1 to 200000.
- When the IEEE 802.1d standard method is used, cost ranges from 1 to 65535.
- When the IEEE 802.1t standard method is used, cost ranges from 1 to 200000000.