A:
If loops occur on a network, it is recommended that you set a large path cost for a port with a low link rate. The port is then selected as the blocking port during spanning tree calculation and its link is blocked.
To set the path cost of a port, perform the following steps:
Step 1: Run the system-view command to enter the system view.
Step 2: (Optional) Run the stp pathcost-standard { dot1d-1998 | dot1t | legacy } command to specify a path cost calculation method.
Step 3: Run the interface interface-type interface-number command to enter the interface view.
Step 4: Run the stp cost cost command to set the path cost of the port.
The path cost range varies with the path cost calculation method used. All switches on the same network must use the same path cost calculation method. Changes to path costs trigger spanning tree recalculation.