The understanding of the sentence that stack switches can increase effective bandwidth is: use the stack module and cable of the switch to connect each switch, so that each switch uses the stack interface to transmit data. The bandwidth of the stack interface is much higher than the interface bandwidth, which is much higher than the rate of direct interface connection. Switch stacks are widely used on enterprise-level switches. They mainly solve the problem of deploying many computers in a laboratory and requiring high-speed transmission between switches. In addition, they are also helpful for switch management.