15-1 CONNECTING DEVICES In this section,we divide connecting devices into five different categories based on the layer in which they operate in a network. Topics discussed in this section: ●Passive Hubs(无源集线器) ●Active Hubs(有源集线器) Bridges(桥) ●Two-Layer Switches(二层交换) ●Routers(路由器) ●Three-Layer Switches(三层交换) ●Gateways(网关) 15.215.2 15-1 CONNECTING DEVICES In this section, we divide connecting devices into five different categories based on the layer in which they operate in a network.  Passive Hubs（无源集线器）  Active Hubs（有源集线器） Bridges（桥）  Two-Layer Switches（二层交换）  Routers（路由器）  Three-Layer Switches（三层交换）  Gateways（网关） Topics discussed in this section: