1-32Follow these steps to configure the path cost for a port in Ethernet port view:To do... Use the command... RemarksEnter system view system-view —Enter Ethernet port view interface interface-typeinterface-number —Configure the path cost for theportstp [ instance instance-id ]cost costRequiredAn MSTP-enabled switch cancalculate path costs for all itsports automatically.Changing the path cost of a port may change the role of the port and put it in state transition. Executingthe stp cost command with the instance-id argument being 0 sets the path cost on the CIST for the port.Configuration example (A)# Configure the path cost of Ethernet 1/0/1 in MSTI 1 to be 2,000.1) Perform this configuration in system view system-view[Sysname] stp interface Ethernet 1/0/1 instance 1 cost 20002) Perform this configuration in Ethernet port view system-view[Sysname] interface Ethernet 1/0/1[Sysname-Ethernet1/0/1] stp instance 1 cost 2000Configuration example (B)# Configure the path cost of Ethernet 1/0/1 in MSTI 1 to be calculated by the MSTP-enabled switchaccording to the IEEE 802.1D-1998 standard.1) Perform this configuration in system view system-view[Sysname] undo stp interface Ethernet 1/0/1 instance 1 cost[Sysname] stp pathcost-standard dot1d-19982) Perform this configuration in Ethernet port view system-view[Sysname] interface Ethernet 1/0/1[Sysname-Ethernet1/0/1] undo stp instance 1 cost[Sysname-Ethernet1/0/1] quit[Sysname] stp pathcost-standard dot1d-1998Configuring Port PriorityPort priority is an important criterion on determining the root port. In the same condition, the port with thesmallest port priority value becomes the root port.A port on an MSTP-enabled switch can have different port priorities and play different roles in differentMSTIs. This enables packets of different VLANs to be forwarded along different physical paths, so thatVLAN-based load balancing can be implemented.You can configure port priority in one of the following two ways.
