Traditional Ethernet LANs run at 10Mbps over a common bus-type design. Stations physically attach to this bus through a hub, repeater or concentrator, creating a broadcast domain. Every station is capable of receiving all transmissions from all stations, but only in a half-duplex mode. This means stations cannot send and receive data simultaneously. Nodes on an Ethernet network transmit information following a simple rule: they listen before speaking. In an Ethernet environment, only one node on the segment is allowed to transmit at any time due to the CSMA/CD protocol (Carrier Sense Multiple Access/Collision Detection). Though this manages packet collisions, it increases transmission time in two ways. First, if two nodes begin speaking at the same time, the information collides; they both must stop transmission and try again later. Second, once a packet is sent from a node, and Ethernet LAN will not transfer any other information until that packet reaches its endpoint. This is what slows up networks. Countless hours have been lost waiting for a LAN to free up.

When a single LAN station is connected to a switched port it may operate in full-duplex mode. Full-duplex does not require collision detection, there is a suspension of MAC protocols. A single device resides on that port, and therefore no collisions will be encountered. Full-duplex switching enables traffic to be sent and received simultaneously. (Hubs between a workgroup and a switch will not run full-duplex, because the hub is governed by collision detection requirements. The workgroup connected to the hub is unswitched Ethernet).

The bottom line is a 24 port 100 Mbps hub is only capable of sharing the full 100 Mbps with all 24-ports, which averages out to 4.16 Mbps for each port. While at the same time a 24-port 100 Mbps Switch has 24 individual 100 Mbps ports. The switch is capable of 2400 Mbps or 2.4 Gigabits per second. Also a switch can operate in full-duplex mode, so it has a theoretical throughput of 4800 Mbps or 4.8 Gbps.