stp pathcost-standard

Function

The stp pathcost-standard command sets the standard used to calculate the path cost.

The undo stp pathcost-standard command restores the default standard used to calculate the path cost.

By default, the IEEE 802.1t is used to calculate the path cost.

Format

stp pathcost-standard { dot1d-1998 | dot1t | legacy }

undo stp pathcost-standard

Parameters

Parameter	Description	Value
dot1d-1998	Indicates IEEE 802.1D standard that is used to calculate the path cost.	-
dot1t	Indicates IEEE 802.1t standard that is used to calculate the path cost.	-
legacy	Indicates Huawei legacy standard that is used to calculate the path cost.	-

Views

System view or MSTP process view

VBST does not support processes. When VBST is running, you cannot run the stp pathcost-standard command in the MSTP process view.

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

A path cost is a port parameter, and is used by a spanning tree protocol to select a link. By calculating path costs, a spanning tree protocol selects stable links, blocks redundant paths, and trims a network into a loop-free network. The path cost range is determined by the path cost calculation standard.

Table 1 lists path costs defined by the IEEE 802.1D-1998 standard, IEEE 802.1t standard, and Huawei legacy standard. Different vendors use different standards.

**Table 1** Path cost list
Interface Rate	Interface Mode	Recommended STP Path Cost
Interface Rate	Interface Mode	IEEE 802.1D-1998 Standard	IEEE 802.1t Standard	Huawei Legacy Standard
0	-	65535	200,000,000	200,000
10 Mbit/s	Half-Duplex	100	2,000,000	2000
	Full-Duplex	99	1,999,999	1999
	Aggregated Link 2 Ports	95	1,000,000	1800
	Aggregated Link 3 Ports	95	666,666	1600
	Aggregated Link 4 Ports	95	500,000	1400
100 Mbit/s	Half-Duplex	19	200,000	200
	Full-Duplex	18	199,999	199
	Aggregated Link 2 Ports	15	100,000	180
	Aggregated Link 3 Ports	15	66,666	160
	Aggregated Link 4 Ports	15	50,000	140
1000 Mbit/s	Full-Duplex	4	20,000	20
	Aggregated Link 2 Ports	3	10,000	18
	Aggregated Link 3 Ports	3	6666	16
	Aggregated Link 4 Ports	3	5000	14
2500 Mbit/s	Full-Duplex	3	8000	17
	Aggregated Link 2 Ports	3	4000	12
	Aggregated Link 3 Ports	3	2666	7
	Aggregated Link 4 Ports	2	2000	2
10 Gbit/s	Full-Duplex	2	2000	2
	Aggregated Link 2 Ports	1	1000	1
	Aggregated Link 3 Ports	1	666	1
	Aggregated Link 4 Ports	1	500	1
40 Gbit/s	Full-Duplex	1	500	1
	Aggregated Link 2 Ports	1	250	1
	Aggregated Link 3 Ports	1	166	1
	Aggregated Link 4 Ports	1	125	1

Precautions

If the path cost calculation standard is changed on a port, the path cost of the port is restored to the default value. The stp cost command can be used to set a path cost for a port.

Usually, all switching devices on the same network use the same path cost calculation standard.

Example

# Use the IEEE 802.1d-1998 to calculate the path cost.

<HUAWEI> system-view

[HUAWEI] stp pathcost-standard dot1d-1998