Spanning-Tree Protocol is a method of preventing layer two switching loops which might otherwise overwhelm the network. There is an election process during which a switch is elected the Root Bridge (master switch). All traffic must pass through this switch before leaving the LAN. A switch can be manually caused to be the Root Bridge (switch) by designating it the root in CLI or manually assigning a BridgeID lower than the other switches within the LAN. Additionally, various other commands may be appropriate including root guard, loop guard, bpdu guard.