3Com 10014298 manual Specify the Standard To BeFollowed in Path Cost Calculation

198CHAPTER 8: STP OPERATION

Configuring the Path Path cost is related to the speed of the link connected to the port. On the MSTP Cost of a Port switch, a port can be configured with different path costs for different STIs. Thus

the traffic from different VLANs can run over different physical links, thereby implementing the VLAN-based load-balancing.

You can configure the path cost of a port in the following ways.

Configuring in System View

Perform the following configuration in system view.

Table 202 Configure the Path Cost of a Port

Operation	Command
Configure the Path Cost of a port.	stp interface interface-list
	instance instance-id cost cost
Restore the default path cost of a port.	undo stp interface interface-list
	instance instance-idcost

Configuring in Ethernet Port View

Perform the following configuration in Ethernet port view.

Table 203 Configure the Path Cost of a Port

Operation	Command
Configure the Path Cost of a port	stp instance instance-idcost
	cost
Restore the default path cost of a port.	undo stp instance instance-id
	cost

For more about the commands, see the Switch 7750 Command Reference Guide.

Upon the change of path cost of a port, MSTP will recalculate the port role and transit the state. When instance-idtakes 0, it indicates to set the path cost on the CIST.

By default, MSTP is responsible for calculating the port path cost.

Specify the Standard To BeFollowed in Path Cost Calculation

The following two standards are currently available on the switch:

■dot1d-1998: The switch calculates the default Path Cost of a port by the IEEE 802.1D-1998 standard.

■dot1t: The switch calculates the default Path Cost of a port by the IEEE 802.1t standard.

■legacy: The switch calculates the default Path Cost of a port by the Huawei-3Com standard.

You can specify the intended standard by using the following commands.