Half-Duplex & Full-Duplex
Half-Duplex & Full-Duplex
· Jomplair · Lexicon Lab

Half-Duplex VS. Full-Duplex

Half-Duplex and Full-Duplex are two distinct communication modes used to describe how data is transmitted over a network. They differ significantly in their definitions, applications, and performance characteristics. Below is a comparative table highlighting their key differences:

Feature

Half-Duplex

Full-Duplex

Definition

Data can be transmitted in both directions, but not simultaneously. Only one device can send or receive at a time.

Data can be transmitted in both directions simultaneously. Devices can send and receive data at the same time.

Communication Mode

Similar to a walkie-talkie: Only one party can speak while the other listens.

Similar to a telephone: Both parties can speak and listen simultaneously.

Applications

- Early Ethernet networks (e.g., 10BASE2, 10BASE5)<br>- Wireless networks (e.g., Wi-Fi)<br>- Shared-medium network environments

- Modern Ethernet networks (e.g., 100BASE-TX, 1000BASE-T)<br>- Fiber optic networks<br>- Point-to-point network environments

Performance

Lower efficiency due to unidirectional transmission at any given time, leading to potential collisions (e.g., CSMA/CD mechanism).

Higher efficiency as bidirectional transmission avoids collisions and maximizes bandwidth utilization.

Collision Detection

Requires collision detection mechanisms (e.g., CSMA/CD) due to potential data collisions.

No collision detection is needed since transmission and reception are independent and do not interfere.

Bandwidth Utilization

Lower, as only half of the bandwidth can be used at any given time.

Higher, as both directions can utilize the full bandwidth simultaneously.

Typical Devices

Hubs, legacy network devices.

Switches, modern network devices.

Latency

Higher, as devices must wait for the other party to finish transmitting before sending data.

Lower, as devices can transmit and receive data simultaneously.

Cost

Lower, due to simpler devices and technology.

Higher, due to more complex devices and technology requirements.

Summary:

  • Half-Duplex is suitable for shared-medium network environments, such as early Ethernet and wireless networks. However, its unidirectional transmission leads to lower efficiency and potential collisions.
  • Full-Duplex is ideal for modern point-to-point network environments, such as switches and fiber optic networks. It enables simultaneous bidirectional transmission, offering higher efficiency and better bandwidth utilization.

In modern networks, Full-Duplex has become the dominant mode due to its superior performance and lower latency, while Half-Duplex is primarily used in specific scenarios or with legacy network equipment.

 

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