Full Duplex vs. Half Duplex

ContentProvidedBy-NVTWhen a switch is connected to an IP device, information is transferred in both directions. The switch sends information to the endpoint device and vice versa. Full duplex (FDX) switches allow for the simultaneous transmission of information between the switch and the endpoint. In a half duplex (HDX) system, communication flows in one direction at a time.

A half duplex system can be compared to the “push-to-talk” nature of a walkie-talkie. When the button is pressed, the receiver is turned off, and the transmitter is activated. When the button is released, the transmitter is turned off, and the receiver is turned back on. The device cannot transmit and receive simultaneously. A full duplex system is like talking on the telephone, in which both parties can speak and listen at the same time.

Symmetrical vs. Asymmetrical Bandwidth

Like full duplex and half duplex, symmetrical and asymmetrical bandwidth will play a significant role in the network’s overall performance and reliability. A switch that can deliver 100Mbps symmetrical, full duplex can transmit and receive at a rate of 100Mbps. Even if it is full duplex, a network switch with asymmetrical bandwidth cannot send AND receive at 100Mbps. Asymmetrical switches will use an uneven split to transmit at 70Mbps and receive at 30Mbps, for example.


In addition to transmission speed, latency also plays a significant role in network performance and service quality. Latency is the time it takes a piece of information (a packet) to reach its destination. Latency may not be as crucial for certain endpoints, such as data terminals. However, for real-time applications like voice calls or live video monitoring, low latency is critical to ensure a good user experience.


Finally, there is the issue of noise, also known as crosstalk. Crosstalk occurs when a signal transmission results in undesired electromagnetic waves that interfere with surrounding equipment or wiring.

Noise production makes a big impact on large deployments where there is a lot of equipment and cabling in one physical space. This issue can be overlooked when testing equipment with just a few devices. However, as the deployment size increases, so does the noise produced, and therefore the interference with other devices. As a result, devices will slow and experience packet loss.

NVT Phybridge Power over Ethernet Switches

NVT Phybridge long-reach Power over Ethernet switches and extenders deliver symmetrical, full duplex, and PoE over any new or existing network infrastructure. We provide industry-leading solutions to make digital transformation projects as simple and rewarding as possible for our customers and partners.