Command Manual – MSTPH3C S7500E Series Ethernet Switches Chapter 1 MSTP Configuration Commands1-191.1.19 stp costSyntaxstp [ instance instance-id ] cost costundo stp [ instance instance-id ] costViewEthernet interface view, port group viewParametersinstance instance-id: Sets the path cost of the port(s) in a particular spanning treeinstance. The effective range of instance-id is 0 to 31, with 0 representing the CIST.cost: Path cost of the port, the effective range of which depends on the path costcalculation standard adopted.DescriptionUse the stp cost command to set the path cost of the port(s) in the specified spanningtree instance or all spanning tree instances.Use the undo stp cost command to restore the system default.By default, the device automatically calculates the path costs of ports in each spanningtree instance based on the corresponding standard.Configured in Ethernet interface view, the setting is effective on the current port only;configured in port group view, the setting is effective on all ports in the port group.If you set instance-id to 0, you are setting the path cost of the port in the CIST. The pathcost setting of a port can affect the role selection of the port. Setting different path costsfor the same port in different spanning tree instances allows different VLAN traffic flowsto be forwarded along different physical links, thus to enable per-VLAN load balancing.When the path cost of a port is changed, MSTP will re-compute the role of the port andinitiate a state transition.If you do not provide instance instance-id, your configuration will take effect in the CISTinstance only.Examples# Set the path cost of port GigabitEthernet 2/0/1 in spanning tree instance 2 to 200. system-view[Sysname] interface GigabitEthernet 2/0/1[Sysname-GigabitEthernet2/0/1] stp instance 2 cost 200
