3Com MSR 50, MSR 30 manual Stp point-to-point, 617

617

Table 110 Link speed vs. path cost

Link speed	Duplex state	802.1D-1998	IEEE 802.1t	Private standard
100Mbps	Single Port	19	200,000	200
	Aggregated	19	100,000	180
	Link 2 Ports	19	66,666	160
	Aggregated
		19	50,000	140
	Link 3 Ports
	Aggregated
	Link 4 Ports
1000Mbps	Single Port	4	20,000	20
	Aggregated	4	10,000	18
	Link 2 Ports	4	6,666	16
	Aggregated
		4	5,000	14
	Link 3 Ports
	Aggregated
	Link 4 Ports
10Gbps	Single Port	2	2,000	2
	Aggregated	2	1,000	1
	Link 2 Ports	2	666	1
	Aggregated
		2	500	1
	Link 3 Ports

Aggregated

Link 4 Ports

In the calculation of the path cost value of an aggregated link, 802.1D-1998 does not take into account the number of ports in the aggregated link. Whereas, 802.1T takes the number of ports in the aggregated link into account. The calculation formula is: Path Cost = 200,000,000/link speed (in 100 kbps), where link speed is the sum of the link speed values of the non-blocked ports in the aggregated link.

Examples # Configure the device to calculate the default path cost for ports based on IEEE 802.1D-1998.

<Sysname> system-view

[Sysname] stp pathcost-standard dot1d-1998

#Configure the device to calculate the default path cost for ports based on IEEE 802.1t.

<Sysname> system-view

[Sysname] stp pathcost-standard dot1t

stp point-to-point

Syntax stp point-to-point { auto force-false force-true }

undo stp point-to-point

View Ethernet interface view, port group view