This article breaks down the differences between L2 and L3 switches in the access layer, analyzes key decision factors like network scale and complexity, and finally provides a practical recommendation. Quality of Service (QoS) refers to enhancing network service for selected traffic across technologies like Ethernet, Frame Relay, and IP-routed networks. You can use QoS to ensure that your applications receive predictable service levels, including data throughput capacity (bandwidth), latency. This white paper introduces the following three types of network switches and further discusses the selection criteria for each switch. The hierarchy Ethernet network is a three-layer integrated setup of networking devices. "Campus Networks Typical Configuration Examples" provides typical campus network networking modes and a variety of deployment examples. We usually follow this order: Internet > WAN > NAT (Router) > Core Layer Switch > Aggregation. The access layer is where endpoints (such as phones, laptops, video-conferencing sets, printers, IoT sensors, IP cameras, and servers) are primarily connecting to the network. FortiSwitch units distribute the ports to plugs.