1-26z If you change the standard that the device uses in calculating the default path cost, the port pathcost value set through the stp cost command will be invalid.z When the path cost of a port is changed, MSTP will re-calculate the role of the port and initiate astate transition. If you use 0 as instance-id, you are setting the path cost of the CIST.Configuration example# Specify that the device use 802.1d-1998 when calculating the default path costs of its ports. system-view[Sysname] stp pathcost-standard dot1d-1998# Set the path cost of GigabitEthernet 1/0/3 on MSTI 2 to 200. system-view[Sysname] interface gigabitethernet 1/0/3[Sysname-GigabitEthernet1/0/3] stp instance 2 cost 200Configuring Port PriorityThe priority of a port is an important factor in determining whether the port can be elected as the rootport of a device. If all other conditions are the same, the port with the highest priority will be elected asthe root port.On an MSTP-enabled device, a port can have different priorities in different MSTIs, and the same portcan play different roles in different MSTIs, so that data of different VLANs can be propagated alongdifferent physical paths, thus implementing per-VLAN load balancing. You can set port priority valuesbased on the actual networking requirements.Make this configuration on the leaf nodes only.Follow these steps to configure the priority of a port or a group of ports:To do... Use the command... RemarksEnter system view system-view —Enter Ethernet interfaceview, or Layer 2aggregate interfaceviewinterface interface-typeinterface-numberEnterinterface viewor port groupviewEnter port group view port-group manualport-group-nameRequiredUse either command.Configure the port prioritystp [ instanceinstance-id ] port prioritypriorityOptional128 for all ports by default.
